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From: Nicolas Iooss <nicolas.iooss@m4x.org>
To: selinux@vger.kernel.org
Subject: [PATCH 5/9] libsepol: reset *p to NULL if sepol_module_package_create fails
Date: Sun,  1 Sep 2019 20:06:32 +0200
Message-ID: <20190901180636.31586-6-nicolas.iooss@m4x.org> (raw)
In-Reply-To: <20190901180636.31586-1-nicolas.iooss@m4x.org>

semodule-utils/semodule_link/semodule_link.c contains:

    static sepol_module_package_t *load_module(char *filename)
    {
        /* ... */
        if (sepol_module_package_create(&p)) {
            /* ... */
            goto bad;

    /* ... */
    bad:
        sepol_module_package_free(p);

When sepol_module_package_create() fails while having successfully
allocated p, it currently frees p without setting it back to NULL. This
causes a use-after-free in load_module().

Prevent this use-after-free by setting sepol_module_package_create's
argument back to NULL when an error happens.

This issue has been found using Infer static analyzer.

Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
---
 libsepol/src/module.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libsepol/src/module.c b/libsepol/src/module.c
index 219355f30d27..3b8a0a59ca68 100644
--- a/libsepol/src/module.c
+++ b/libsepol/src/module.c
@@ -124,8 +124,10 @@ int sepol_module_package_create(sepol_module_package_t ** p)
 		return -1;
 
 	rc = module_package_init(*p);
-	if (rc < 0)
+	if (rc < 0) {
 		free(*p);
+		*p = NULL;
+	}
 
 	return rc;
 }
-- 
2.22.0


  parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-01 18:06 [PATCH 0/9] Fix issues found by static analyzers Nicolas Iooss
2019-09-01 18:06 ` [PATCH 1/9] semodule-utils: fix comparison with argc Nicolas Iooss
2019-09-01 18:06 ` [PATCH 2/9] libsepol/cil: help static analyzers by aborting when an allocation fails Nicolas Iooss
2019-09-10 18:48   ` [Non-DoD Source] " jwcart2
2019-09-01 18:06 ` [PATCH 3/9] libsepol: do not dereference a failed allocated pointer Nicolas Iooss
2019-09-10 18:52   ` [Non-DoD Source] " jwcart2
2019-09-10 20:11     ` jwcart2
2019-09-01 18:06 ` [PATCH 4/9] libsepol: do not dereference scope if it can be NULL Nicolas Iooss
2019-09-01 18:06 ` Nicolas Iooss [this message]
2019-09-01 18:06 ` [PATCH 6/9] libsepol/cil: do not dereference perm_value_to_cil when it has not been allocated Nicolas Iooss
2019-09-01 18:06 ` [PATCH 7/9] python/chcat: remove unnecessary assignment Nicolas Iooss
2019-09-01 18:06 ` [PATCH 8/9] python/sepolicy: remove unnecessary pass statement Nicolas Iooss
2019-09-01 18:06 ` [PATCH 9/9] libsepol/tests: do not dereference a NULL pointer Nicolas Iooss
2019-09-16 16:46 ` [Non-DoD Source] [PATCH 0/9] Fix issues found by static analyzers jwcart2
2019-09-17 15:01   ` jwcart2

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