From 422bec25ae4a1ab03fd4d6f728695ed279173b18 Mon Sep 17 00:00:00 2001
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>

Upstream-Status: Backport [https://git.kernel.org/pub/scm/libs/libcap/libcap.git/commit/?id=422bec25ae4a1ab03fd4d6f728695ed279173b18]
CVE: CVE-2023-2603
Signed-off-by: Vivek Kumbhar <vkumbhar@mvista.com>

---
 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) {
-- 
2.25.1

