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From: "Andrew G. Morgan" <morgan@kernel.org>
Date: Wed, 3 May 2023 19:44:22 -0700
Subject: 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>
Origin: upstream, https://git.kernel.org/pub/scm/libs/libcap/libcap.git/commit/?id=422bec25ae4a1ab03fd4d6f728695ed279173b18
---
libcap/cap_alloc.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/libcap/cap_alloc.c b/libcap/cap_alloc.c
index c826e7a..25f9981 100644
--- a/libcap/cap_alloc.c
+++ b/libcap/cap_alloc.c
@@ -105,15 +105,17 @@ 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) {
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