diff options
Diffstat (limited to 'source/l/glibc/patches/glibc.CVE-2023-4911.patch')
| -rw-r--r-- | source/l/glibc/patches/glibc.CVE-2023-4911.patch | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/source/l/glibc/patches/glibc.CVE-2023-4911.patch b/source/l/glibc/patches/glibc.CVE-2023-4911.patch new file mode 100644 index 000000000..a790a8305 --- /dev/null +++ b/source/l/glibc/patches/glibc.CVE-2023-4911.patch @@ -0,0 +1,173 @@ +From 1056e5b4c3f2d90ed2b4a55f96add28da2f4c8fa Mon Sep 17 00:00:00 2001 +From: Siddhesh Poyarekar <siddhesh@sourceware.org> +Date: Tue, 19 Sep 2023 18:39:32 -0400 +Subject: [PATCH] tunables: Terminate if end of input is reached + (CVE-2023-4911) + +The string parsing routine may end up writing beyond bounds of tunestr +if the input tunable string is malformed, of the form name=name=val. +This gets processed twice, first as name=name=val and next as name=val, +resulting in tunestr being name=name=val:name=val, thus overflowing +tunestr. + +Terminate the parsing loop at the first instance itself so that tunestr +does not overflow. + +This also fixes up tst-env-setuid-tunables to actually handle failures +correct and add new tests to validate the fix for this CVE. + +Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org> +Reviewed-by: Carlos O'Donell <carlos@redhat.com> +--- + NEWS | 5 +++++ + elf/dl-tunables.c | 17 +++++++++------- + elf/tst-env-setuid-tunables.c | 37 +++++++++++++++++++++++++++-------- + 3 files changed, 44 insertions(+), 15 deletions(-) + +diff --git a/NEWS b/NEWS +index a94650da64..cc4b81f0ac 100644 +--- a/NEWS ++++ b/NEWS +@@ -64,6 +64,11 @@ Security related changes: + an application calls getaddrinfo for AF_INET6 with AI_CANONNAME, + AI_ALL and AI_V4MAPPED flags set. + ++ CVE-2023-4911: If a tunable of the form NAME=NAME=VAL is passed in the ++ environment of a setuid program and NAME is valid, it may result in a ++ buffer overflow, which could be exploited to achieve escalated ++ privileges. This flaw was introduced in glibc 2.34. ++ + The following bugs are resolved with this release: + + [The release manager will add the list generated by +diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c +index 62b7332d95..cae67efa0a 100644 +--- a/elf/dl-tunables.c ++++ b/elf/dl-tunables.c +@@ -180,11 +180,7 @@ parse_tunables (char *tunestr, char *valstring) + /* If we reach the end of the string before getting a valid name-value + pair, bail out. */ + if (p[len] == '\0') +- { +- if (__libc_enable_secure) +- tunestr[off] = '\0'; +- return; +- } ++ break; + + /* We did not find a valid name-value pair before encountering the + colon. */ +@@ -244,9 +240,16 @@ parse_tunables (char *tunestr, char *valstring) + } + } + +- if (p[len] != '\0') +- p += len + 1; ++ /* We reached the end while processing the tunable string. */ ++ if (p[len] == '\0') ++ break; ++ ++ p += len + 1; + } ++ ++ /* Terminate tunestr before we leave. */ ++ if (__libc_enable_secure) ++ tunestr[off] = '\0'; + } + + /* Enable the glibc.malloc.check tunable in SETUID/SETGID programs only when +diff --git a/elf/tst-env-setuid-tunables.c b/elf/tst-env-setuid-tunables.c +index 7dfb0e073a..f0b92c97e7 100644 +--- a/elf/tst-env-setuid-tunables.c ++++ b/elf/tst-env-setuid-tunables.c +@@ -50,6 +50,8 @@ const char *teststrings[] = + "glibc.malloc.perturb=0x800:not_valid.malloc.check=2:glibc.malloc.mmap_threshold=4096", + "glibc.not_valid.check=2:glibc.malloc.mmap_threshold=4096", + "not_valid.malloc.check=2:glibc.malloc.mmap_threshold=4096", ++ "glibc.malloc.mmap_threshold=glibc.malloc.mmap_threshold=4096", ++ "glibc.malloc.check=2", + "glibc.malloc.garbage=2:glibc.maoc.mmap_threshold=4096:glibc.malloc.check=2", + "glibc.malloc.check=4:glibc.malloc.garbage=2:glibc.maoc.mmap_threshold=4096", + ":glibc.malloc.garbage=2:glibc.malloc.check=1", +@@ -68,6 +70,8 @@ const char *resultstrings[] = + "glibc.malloc.perturb=0x800:glibc.malloc.mmap_threshold=4096", + "glibc.malloc.mmap_threshold=4096", + "glibc.malloc.mmap_threshold=4096", ++ "glibc.malloc.mmap_threshold=glibc.malloc.mmap_threshold=4096", ++ "", + "", + "", + "", +@@ -81,11 +85,18 @@ test_child (int off) + { + const char *val = getenv ("GLIBC_TUNABLES"); + ++ printf (" [%d] GLIBC_TUNABLES is %s\n", off, val); ++ fflush (stdout); + if (val != NULL && strcmp (val, resultstrings[off]) == 0) + return 0; + + if (val != NULL) +- printf ("[%d] Unexpected GLIBC_TUNABLES VALUE %s\n", off, val); ++ printf (" [%d] Unexpected GLIBC_TUNABLES VALUE %s, expected %s\n", ++ off, val, resultstrings[off]); ++ else ++ printf (" [%d] GLIBC_TUNABLES environment variable absent\n", off); ++ ++ fflush (stdout); + + return 1; + } +@@ -106,21 +117,26 @@ do_test (int argc, char **argv) + if (ret != 0) + exit (1); + +- exit (EXIT_SUCCESS); ++ /* Special return code to make sure that the child executed all the way ++ through. */ ++ exit (42); + } + else + { +- int ret = 0; +- + /* Spawn tests. */ + for (int i = 0; i < array_length (teststrings); i++) + { + char buf[INT_BUFSIZE_BOUND (int)]; + +- printf ("Spawned test for %s (%d)\n", teststrings[i], i); ++ printf ("[%d] Spawned test for %s\n", i, teststrings[i]); + snprintf (buf, sizeof (buf), "%d\n", i); ++ fflush (stdout); + if (setenv ("GLIBC_TUNABLES", teststrings[i], 1) != 0) +- exit (1); ++ { ++ printf (" [%d] Failed to set GLIBC_TUNABLES: %m", i); ++ support_record_failure (); ++ continue; ++ } + + int status = support_capture_subprogram_self_sgid (buf); + +@@ -128,9 +144,14 @@ do_test (int argc, char **argv) + if (WEXITSTATUS (status) == EXIT_UNSUPPORTED) + return EXIT_UNSUPPORTED; + +- ret |= status; ++ if (WEXITSTATUS (status) != 42) ++ { ++ printf (" [%d] child failed with status %d\n", i, ++ WEXITSTATUS (status)); ++ support_record_failure (); ++ } + } +- return ret; ++ return 0; + } + } + +-- +2.39.3 + + |