diff options
Diffstat (limited to 'patches/glibc-2.20/0003-CVE-2014-7817-wordexp-fails-to-honour-WRDE_NOCMD.patch')
| -rw-r--r-- | patches/glibc-2.20/0003-CVE-2014-7817-wordexp-fails-to-honour-WRDE_NOCMD.patch | 166 |
1 files changed, 0 insertions, 166 deletions
diff --git a/patches/glibc-2.20/0003-CVE-2014-7817-wordexp-fails-to-honour-WRDE_NOCMD.patch b/patches/glibc-2.20/0003-CVE-2014-7817-wordexp-fails-to-honour-WRDE_NOCMD.patch deleted file mode 100644 index 41afda4..0000000 --- a/patches/glibc-2.20/0003-CVE-2014-7817-wordexp-fails-to-honour-WRDE_NOCMD.patch +++ /dev/null @@ -1,166 +0,0 @@ -From: Carlos O'Donell <carlos@redhat.com> -Date: Wed, 19 Nov 2014 11:44:12 -0500 -Subject: [PATCH] CVE-2014-7817: wordexp fails to honour WRDE_NOCMD. - -The function wordexp() fails to properly handle the WRDE_NOCMD -flag when processing arithmetic inputs in the form of "$((... ``))" -where "..." can be anything valid. The backticks in the arithmetic -epxression are evaluated by in a shell even if WRDE_NOCMD forbade -command substitution. This allows an attacker to attempt to pass -dangerous commands via constructs of the above form, and bypass -the WRDE_NOCMD flag. This patch fixes this by checking for WRDE_NOCMD -in exec_comm(), the only place that can execute a shell. All other -checks for WRDE_NOCMD are superfluous and removed. - -We expand the testsuite and add 3 new regression tests of roughly -the same form but with a couple of nested levels. - -On top of the 3 new tests we add fork validation to the WRDE_NOCMD -testing. If any forks are detected during the execution of a wordexp() -call with WRDE_NOCMD, the test is marked as failed. This is slightly -heuristic since vfork might be used in the future, but it provides a -higher level of assurance that no shells were executed as part of -command substitution with WRDE_NOCMD in effect. In addition it doesn't -require libpthread or libdl, instead we use the public implementation -namespace function __register_atfork (already part of the public ABI -for libpthread). - -Tested on x86_64 with no regressions. - -(cherry picked from commit a39208bd7fb76c1b01c127b4c61f9bfd915bfe7c) ---- - posix/wordexp-test.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ - posix/wordexp.c | 16 ++++------------ - 2 files changed, 48 insertions(+), 12 deletions(-) - -diff --git a/posix/wordexp-test.c b/posix/wordexp-test.c -index 4957006da74b..bdd65e439fe5 100644 ---- a/posix/wordexp-test.c -+++ b/posix/wordexp-test.c -@@ -27,6 +27,25 @@ - - #define IFS " \n\t" - -+extern void *__dso_handle __attribute__ ((__weak__, __visibility__ ("hidden"))); -+extern int __register_atfork (void (*) (void), void (*) (void), void (*) (void), void *); -+ -+static int __app_register_atfork (void (*prepare) (void), void (*parent) (void), void (*child) (void)) -+{ -+ return __register_atfork (prepare, parent, child, -+ &__dso_handle == NULL ? NULL : __dso_handle); -+} -+ -+/* Number of forks seen. */ -+static int registered_forks; -+ -+/* For each fork increment the fork count. */ -+static void -+register_fork (void) -+{ -+ registered_forks++; -+} -+ - struct test_case_struct - { - int retval; -@@ -206,6 +225,12 @@ struct test_case_struct - { WRDE_SYNTAX, NULL, "$((2+))", 0, 0, { NULL, }, IFS }, - { WRDE_SYNTAX, NULL, "`", 0, 0, { NULL, }, IFS }, - { WRDE_SYNTAX, NULL, "$((010+4+))", 0, 0, { NULL }, IFS }, -+ /* Test for CVE-2014-7817. We test 3 combinations of command -+ substitution inside an arithmetic expression to make sure that -+ no commands are executed and error is returned. */ -+ { WRDE_CMDSUB, NULL, "$((`echo 1`))", WRDE_NOCMD, 0, { NULL, }, IFS }, -+ { WRDE_CMDSUB, NULL, "$((1+`echo 1`))", WRDE_NOCMD, 0, { NULL, }, IFS }, -+ { WRDE_CMDSUB, NULL, "$((1+$((`echo 1`))))", WRDE_NOCMD, 0, { NULL, }, IFS }, - - { -1, NULL, NULL, 0, 0, { NULL, }, IFS }, - }; -@@ -258,6 +283,15 @@ main (int argc, char *argv[]) - return -1; - } - -+ /* If we are not allowed to do command substitution, we install -+ fork handlers to verify that no forks happened. No forks should -+ happen at all if command substitution is disabled. */ -+ if (__app_register_atfork (register_fork, NULL, NULL) != 0) -+ { -+ printf ("Failed to register fork handler.\n"); -+ return -1; -+ } -+ - for (test = 0; test_case[test].retval != -1; test++) - if (testit (&test_case[test])) - ++fail; -@@ -367,6 +401,9 @@ testit (struct test_case_struct *tc) - - printf ("Test %d (%s): ", ++tests, tc->words); - -+ if (tc->flags & WRDE_NOCMD) -+ registered_forks = 0; -+ - if (tc->flags & WRDE_APPEND) - { - /* initial wordexp() call, to be appended to */ -@@ -378,6 +415,13 @@ testit (struct test_case_struct *tc) - } - retval = wordexp (tc->words, &we, tc->flags); - -+ if ((tc->flags & WRDE_NOCMD) -+ && (registered_forks > 0)) -+ { -+ printf ("FAILED fork called for WRDE_NOCMD\n"); -+ return 1; -+ } -+ - if (tc->flags & WRDE_DOOFFS) - start_offs = sav_we.we_offs; - -diff --git a/posix/wordexp.c b/posix/wordexp.c -index b6b65dd993ec..26f3a2653feb 100644 ---- a/posix/wordexp.c -+++ b/posix/wordexp.c -@@ -893,6 +893,10 @@ exec_comm (char *comm, char **word, size_t *word_length, size_t *max_length, - pid_t pid; - int noexec = 0; - -+ /* Do nothing if command substitution should not succeed. */ -+ if (flags & WRDE_NOCMD) -+ return WRDE_CMDSUB; -+ - /* Don't fork() unless necessary */ - if (!comm || !*comm) - return 0; -@@ -2082,9 +2086,6 @@ parse_dollars (char **word, size_t *word_length, size_t *max_length, - } - } - -- if (flags & WRDE_NOCMD) -- return WRDE_CMDSUB; -- - (*offset) += 2; - return parse_comm (word, word_length, max_length, words, offset, flags, - quoted? NULL : pwordexp, ifs, ifs_white); -@@ -2196,9 +2197,6 @@ parse_dquote (char **word, size_t *word_length, size_t *max_length, - break; - - case '`': -- if (flags & WRDE_NOCMD) -- return WRDE_CMDSUB; -- - ++(*offset); - error = parse_backtick (word, word_length, max_length, words, - offset, flags, NULL, NULL, NULL); -@@ -2357,12 +2355,6 @@ wordexp (const char *words, wordexp_t *pwordexp, int flags) - break; - - case '`': -- if (flags & WRDE_NOCMD) -- { -- error = WRDE_CMDSUB; -- goto do_error; -- } -- - ++words_offset; - error = parse_backtick (&word, &word_length, &max_length, words, - &words_offset, flags, pwordexp, ifs, |