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From: Dominic Chen <d.c.ddcc@gmail.com>
To: musl@lists.openwall.com
Subject: [musl] [PATCH] Fix crash in malloc_usable_size() if nullptr
Date: Wed, 25 Nov 2020 02:53:16 -0500	[thread overview]
Message-ID: <fad9eac5-622d-b317-70da-311f6cac3557@gmail.com> (raw)

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Please CC me on replies.

According to the manual for malloc_usable_size(), zero should be 
returned if the input pointer is NULL. Currently, this is not checked, 
which can result in SIGSEGV at runtime.

Thanks,

Dominic


[-- Attachment #2: patch.diff --]
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diff --git a/src/malloc/mallocng/malloc_usable_size.c b/src/malloc/mallocng/malloc_usable_size.c
index a440a4ea..ce6a960c 100644
--- a/src/malloc/mallocng/malloc_usable_size.c
+++ b/src/malloc/mallocng/malloc_usable_size.c
@@ -3,6 +3,7 @@
 
 size_t malloc_usable_size(void *p)
 {
+	if (!p) return 0;
 	struct meta *g = get_meta(p);
 	int idx = get_slot_index(p);
 	size_t stride = get_stride(g);

                 reply	other threads:[~2020-11-25  7:53 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

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