diff --git a/glibc-rh1167569.patch b/glibc-rh1167569.patch new file mode 100644 index 0000000..bd9ba56 --- /dev/null +++ b/glibc-rh1167569.patch @@ -0,0 +1,164 @@ +commit 33ceaf6187b31ea15284ac65131749e1cb68d2ae +Author: Carlos O'Donell +Date: Wed Nov 19 11:44:12 2014 -0500 + + 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) + +diff --git a/posix/wordexp-test.c b/posix/wordexp-test.c +index 4957006..bdd65e4 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 b6b65dd..26f3a26 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, diff --git a/glibc.spec b/glibc.spec index 25b62a2..9a32b31 100644 --- a/glibc.spec +++ b/glibc.spec @@ -1,6 +1,6 @@ %define glibcsrcdir glibc-2.20 %define glibcversion 2.20 -%define glibcrelease 7%{?dist} +%define glibcrelease 8%{?dist} # Pre-release tarballs are pulled in from git using a command that is # effectively: # @@ -207,6 +207,7 @@ Patch0051: %{name}-disable-rwlock-elision.patch # ############################################################################## Patch1001: %{name}-rh1133508.patch +Patch1002: %{name}-rh1167569.patch ############################################################################## # @@ -575,6 +576,7 @@ package or when debugging this package. %patch0050 -p1 %patch1001 -p1 %patch0051 -p1 +%patch1002 -p1 ############################################################################## # %%prep - Additional prep required... @@ -1710,6 +1712,9 @@ rm -f *.filelist* %endif %changelog +* Fri Feb 27 2015 Siddhesh Poyarekar - 2.20-8 +- wordexp fails to honour WRDE_NOCMD (CVE-2014-7817, #1167569). + * Tue Jan 06 2015 Siddhesh Poyarekar - 2.20-7 - Remove LIB_LANG since we don't install locales in /usr/lib/locale anymore. - Don't own any directories in /usr/share/locale (#1167445).