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| author | Siddhesh Poyarekar <siddhesh@sourceware.org> | 2023-09-19 18:39:32 -0400 |
|---|---|---|
| committer | Siddhesh Poyarekar <siddhesh@sourceware.org> | 2023-10-02 15:35:29 -0400 |
| commit | 1056e5b4c3f2d90ed2b4a55f96add28da2f4c8fa (patch) | |
| tree | 7c97228a74e8790ae0a48a64254bfb977922dff6 /elf/dl-tunables.c | |
| parent | 0d5f9ea97f1b39f2a855756078771673a68497e1 (diff) | |
| download | glibc-1056e5b4c3f2d90ed2b4a55f96add28da2f4c8fa.zip glibc-1056e5b4c3f2d90ed2b4a55f96add28da2f4c8fa.tar.gz glibc-1056e5b4c3f2d90ed2b4a55f96add28da2f4c8fa.tar.bz2 | |
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>
Diffstat (limited to 'elf/dl-tunables.c')
| -rw-r--r-- | elf/dl-tunables.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c index 62b7332..cae67ef 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 |