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From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: barebox@lists.infradead.org
Cc: Ahmad Fatoum <a.fatoum@pengutronix.de>
Subject: [PATCH 1/2] test: self: malloc: fix double free after expect_alloc_fail
Date: Tue, 21 Oct 2025 16:54:13 +0200	[thread overview]
Message-ID: <20251021145420.1274668-1-a.fatoum@pengutronix.de> (raw)

If the realloc call unexpectedly succeeds, the p pointer is invalidated,
but it's free'd unconditionally later on, which triggers a
user-after-free.

Account for this by zeroing p when it becomes stale.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 test/self/malloc.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/test/self/malloc.c b/test/self/malloc.c
index 52f9fc344c1a..a60e95b2233f 100644
--- a/test/self/malloc.c
+++ b/test/self/malloc.c
@@ -109,9 +109,15 @@ static void test_malloc(void)
 
 	if (mem_malloc_size) {
 		tmp = expect_alloc_fail(realloc(p, mem_malloc_size));
+		if (tmp)
+			p = NULL;
+
 		free(tmp);
 
 		tmp = expect_alloc_fail(realloc(p, RELOC_HIDE(MALLOC_MAX_SIZE, -1)));
+		if (tmp)
+			p = NULL;
+
 		free(tmp);
 	} else {
 		skipped_tests += 2;
-- 
2.47.3




             reply	other threads:[~2025-10-21 14:54 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-21 14:54 Ahmad Fatoum [this message]
2025-10-21 14:54 ` [PATCH 2/2] test: self: malloc: fix false positive when malloc store is registered Ahmad Fatoum
2025-10-22  6:27 ` [PATCH 1/2] test: self: malloc: fix double free after expect_alloc_fail Sascha Hauer

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