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| author | Andrew G. Morgan <morgan@kernel.org> | 2023-05-03 19:44:22 -0700 |
|---|---|---|
| committer | Andrew G. Morgan <morgan@kernel.org> | 2023-05-09 18:49:46 -0700 |
| commit | 422bec25ae4a1ab03fd4d6f728695ed279173b18 (patch) | |
| tree | ad410b049eb57ce24fd45c664e8d253feaa31393 | |
| parent | bc6b36682f188020ee4770fae1d41bde5b2c97bb (diff) | |
| download | libcap-422bec25ae4a1ab03fd4d6f728695ed279173b18.tar.gz | |
Large strings can confuse libcap's internal strdup code.
Avoid something subtle with really long strings: 1073741823 should
be enough for anybody. This is an improved fix over something attempted
in libcap-2.55 to address some static analysis findings.
Reviewing the library, cap_proc_root() and cap_launcher_set_chroot()
are the only two calls where the library is potentially exposed to a
user controlled string input.
Credit for finding this bug in libcap goes to Richard Weinberger of
X41 D-Sec GmbH (https://x41-dsec.de/) who performed a security audit
of the libcap source code in April of 2023. The audit was sponsored
by the Open Source Technology Improvement Fund (https://ostif.org/).
Audit ref: LCAP-CR-23-02 (CVE-2023-2603)
Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
| -rw-r--r-- | libcap/cap_alloc.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/libcap/cap_alloc.c b/libcap/cap_alloc.c index 59fe503..504abd2 100644 --- a/libcap/cap_alloc.c +++ b/libcap/cap_alloc.c @@ -106,15 +106,17 @@ __attribute__((visibility ("hidden"))) char *_libcap_strdup(const char *old) errno = EINVAL; return NULL; } - len = strlen(old) + 1 + 2*sizeof(__u32); - if (len < sizeof(struct _cap_alloc_s)) { - len = sizeof(struct _cap_alloc_s); - } - if ((len & 0xffffffff) != len) { + + len = strlen(old); + if ((len & 0x3fffffff) != len) { _cap_debug("len is too long for libcap to manage"); errno = EINVAL; return NULL; } + len += 1 + 2*sizeof(__u32); + if (len < sizeof(struct _cap_alloc_s)) { + len = sizeof(struct _cap_alloc_s); + } raw_data = calloc(1, len); if (raw_data == NULL) { |