From d701c3a0a506fa48855b91e511eb6e9348d634da Mon Sep 17 00:00:00 2001 From: Paul Pluzhnikov Date: Wed, 18 Jan 2017 12:28:50 -0800 Subject: Fix catopen() Multiple unbounded stack allocations (BZ17905, CVE-2015-8779) --- README.google | 8 ++++++++ catgets/Makefile | 8 ++++++-- catgets/catgets.c | 19 ++++++++++++------- catgets/open_catalog.c | 23 ++++++++++++++--------- catgets/tst-catgets.c | 31 +++++++++++++++++++++++++++++++ 5 files changed, 71 insertions(+), 18 deletions(-) diff --git a/README.google b/README.google index 6cd1216..fef32de 100644 --- a/README.google +++ b/README.google @@ -649,3 +649,11 @@ misc/hsearch_r.c https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b5cba5cff937e5336ff23380785da80cab09146c https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=3c9e8d9477aba0f514171bb4706670052544479b (stanshebs, backport) + +catgets/Makefile +catgets/catgets.c +catgets/open_catalog.c +catgets/tst-catgets.c + Fix catopen() Multiple unbounded stack allocations (BZ17905, CVE-2015-8779) + https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=0f58539030e436449f79189b6edab17d7479796e + (stanshebs, backport) diff --git a/catgets/Makefile b/catgets/Makefile index c95442d..5cca3af 100644 --- a/catgets/Makefile +++ b/catgets/Makefile @@ -46,13 +46,14 @@ CPPFLAGS-gencat = -DNOT_IN_libc generated = de.msg test1.cat test1.h test2.cat test2.h sample.SJIS.cat \ test-gencat.h +generated += tst-catgets.mtrace tst-catgets-mem.out generated-dirs = de -tst-catgets-ENV = NLSPATH="$(objpfx)%l/%N.cat" LANG=de +tst-catgets-ENV = NLSPATH="$(objpfx)%l/%N.cat" LANG=de MALLOC_TRACE=$(objpfx)tst-catgets.mtrace ifeq ($(run-built-tests),yes) tests: $(objpfx)de/libc.cat $(objpfx)test1.cat $(objpfx)test2.cat \ - $(objpfx)test-gencat.out + $(objpfx)test-gencat.out $(objpfx)tst-catgets-mem.out # This test just checks whether the program produces any error or not. # The result is not tested. $(objpfx)test1.cat: test1.msg $(objpfx)gencat @@ -80,4 +81,7 @@ $(objpfx)test-gencat.out: test-gencat.sh $(objpfx)test-gencat \ $(objpfx)sample.SJIS.cat: sample.SJIS $(objpfx)gencat GCONV_PATH=$(common-objpfx)iconvdata LC_ALL=C \ $(built-program-cmd) -H $(objpfx)test-gencat.h < $(word 1,$^) > $@ + +$(objpfx)tst-catgets-mem.out: $(objpfx)tst-catgets.out + $(common-objpfx)malloc/mtrace $(objpfx)tst-catgets.mtrace > $@ endif diff --git a/catgets/catgets.c b/catgets/catgets.c index eac2827..820c0f6 100644 --- a/catgets/catgets.c +++ b/catgets/catgets.c @@ -16,7 +16,6 @@ License along with the GNU C Library; if not, see . */ -#include #include #include #include @@ -35,6 +34,7 @@ catopen (const char *cat_name, int flag) __nl_catd result; const char *env_var = NULL; const char *nlspath = NULL; + char *tmp = NULL; if (strchr (cat_name, '/') == NULL) { @@ -54,7 +54,10 @@ catopen (const char *cat_name, int flag) { /* Append the system dependent directory. */ size_t len = strlen (nlspath) + 1 + sizeof NLSPATH; - char *tmp = alloca (len); + tmp = malloc (len); + + if (__glibc_unlikely (tmp == NULL)) + return (nl_catd) -1; __stpcpy (__stpcpy (__stpcpy (tmp, nlspath), ":"), NLSPATH); nlspath = tmp; @@ -65,16 +68,18 @@ catopen (const char *cat_name, int flag) result = (__nl_catd) malloc (sizeof (*result)); if (result == NULL) - /* We cannot get enough memory. */ - return (nl_catd) -1; - - if (__open_catalog (cat_name, nlspath, env_var, result) != 0) + { + /* We cannot get enough memory. */ + result = (nl_catd) -1; + } + else if (__open_catalog (cat_name, nlspath, env_var, result) != 0) { /* Couldn't open the file. */ free ((void *) result); - return (nl_catd) -1; + result = (nl_catd) -1; } + free (tmp); return (nl_catd) result; } diff --git a/catgets/open_catalog.c b/catgets/open_catalog.c index bc44f98..5fa4011 100644 --- a/catgets/open_catalog.c +++ b/catgets/open_catalog.c @@ -47,6 +47,7 @@ __open_catalog (const char *cat_name, const char *nlspath, const char *env_var, size_t tab_size; const char *lastp; int result = -1; + char *buf = NULL; if (strchr (cat_name, '/') != NULL || nlspath == NULL) fd = open_not_cancel_2 (cat_name, O_RDONLY); @@ -57,23 +58,23 @@ __open_catalog (const char *cat_name, const char *nlspath, const char *env_var, if (__builtin_expect (bufact + (n) >= bufmax, 0)) \ { \ char *old_buf = buf; \ - bufmax += 256 + (n); \ - buf = (char *) alloca (bufmax); \ - memcpy (buf, old_buf, bufact); \ + bufmax += (bufmax < 256 + (n)) ? 256 + (n) : bufmax; \ + buf = realloc (buf, bufmax); \ + if (__glibc_unlikely (buf == NULL)) \ + { \ + free (old_buf); \ + return -1; \ + } \ } /* The RUN_NLSPATH variable contains a colon separated list of descriptions where we expect to find catalogs. We have to recognize certain % substitutions and stop when we found the first existing file. */ - char *buf; size_t bufact; - size_t bufmax; + size_t bufmax = 0; size_t len; - buf = NULL; - bufmax = 0; - fd = -1; while (*run_nlspath != '\0') { @@ -188,7 +189,10 @@ __open_catalog (const char *cat_name, const char *nlspath, const char *env_var, /* Avoid dealing with directories and block devices */ if (__builtin_expect (fd, 0) < 0) - return -1; + { + free (buf); + return -1; + } if (__builtin_expect (__fxstat64 (_STAT_VER, fd, &st), 0) < 0) goto close_unlock_return; @@ -325,6 +329,7 @@ __open_catalog (const char *cat_name, const char *nlspath, const char *env_var, /* Release the lock again. */ close_unlock_return: close_not_cancel_no_status (fd); + free (buf); return result; } diff --git a/catgets/tst-catgets.c b/catgets/tst-catgets.c index fdaa834..3e1fe84 100644 --- a/catgets/tst-catgets.c +++ b/catgets/tst-catgets.c @@ -1,7 +1,10 @@ +#include #include #include #include +#include #include +#include static const char *msgs[] = @@ -12,6 +15,33 @@ static const char *msgs[] = }; #define nmsgs (sizeof (msgs) / sizeof (msgs[0])) + +/* Test for unbounded alloca. */ +static int +do_bz17905 (void) +{ + char *buf; + struct rlimit rl; + nl_catd result; + + const int sz = 1024 * 1024; + + getrlimit (RLIMIT_STACK, &rl); + rl.rlim_cur = sz; + setrlimit (RLIMIT_STACK, &rl); + + buf = malloc (sz + 1); + memset (buf, 'A', sz); + buf[sz] = '\0'; + setenv ("NLSPATH", buf, 1); + + result = catopen (buf, NL_CAT_LOCALE); + assert (result == (nl_catd) -1); + + free (buf); + return 0; +} + #define ROUNDS 5 int @@ -62,5 +92,6 @@ main (void) } } + result += do_bz17905 (); return result; } -- cgit v1.1