56 lines
1.8 KiB
Diff
56 lines
1.8 KiB
Diff
From 422bec25ae4a1ab03fd4d6f728695ed279173b18 Mon Sep 17 00:00:00 2001
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From: "Andrew G. Morgan" <morgan@kernel.org>
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Date: Wed, 3 May 2023 19:44:22 -0700
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Subject: [PATCH] Large strings can confuse libcap's internal strdup code.
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Avoid something subtle with really long strings: 1073741823 should
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be enough for anybody. This is an improved fix over something attempted
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in libcap-2.55 to address some static analysis findings.
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Reviewing the library, cap_proc_root() and cap_launcher_set_chroot()
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are the only two calls where the library is potentially exposed to a
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user controlled string input.
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Credit for finding this bug in libcap goes to Richard Weinberger of
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X41 D-Sec GmbH (https://x41-dsec.de/) who performed a security audit
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of the libcap source code in April of 2023. The audit was sponsored
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by the Open Source Technology Improvement Fund (https://ostif.org/).
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Audit ref: LCAP-CR-23-02 (CVE-2023-2603)
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Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
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---
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libcap/cap_alloc.c | 12 +++++++-----
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1 file changed, 7 insertions(+), 5 deletions(-)
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diff --git a/libcap/cap_alloc.c b/libcap/cap_alloc.c
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index 59fe503..504abd2 100644
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--- a/libcap/cap_alloc.c
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+++ b/libcap/cap_alloc.c
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@@ -106,15 +106,17 @@ __attribute__((visibility ("hidden"))) char *_libcap_strdup(const char *old)
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errno = EINVAL;
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return NULL;
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}
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- len = strlen(old) + 1 + 2*sizeof(__u32);
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- if (len < sizeof(struct _cap_alloc_s)) {
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- len = sizeof(struct _cap_alloc_s);
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- }
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- if ((len & 0xffffffff) != len) {
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+
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+ len = strlen(old);
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+ if ((len & 0x3fffffff) != len) {
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_cap_debug("len is too long for libcap to manage");
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errno = EINVAL;
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return NULL;
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}
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+ len += 1 + 2*sizeof(__u32);
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+ if (len < sizeof(struct _cap_alloc_s)) {
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+ len = sizeof(struct _cap_alloc_s);
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+ }
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raw_data = calloc(1, len);
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if (raw_data == NULL) {
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--
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2.27.0
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