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authorStefan Hajnoczi <stefanha@redhat.com>2016-09-13 09:56:27 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2016-09-13 11:00:55 +0100
commit0647d47cc184da587c76743546b6af6dfdb8f1da (patch)
tree7c2f3964fb1e4b6408cddd7deeddb2423601a9a9 /block/qcow2.c
parent7263da78045dc91cc207f350911efe4259e99b3c (diff)
qcow2: avoid memcpy(dst, NULL, len)
Section "7.1.4 Use of library functions" in the C99 standard says: If an argument to a function has an invalid value (such as [...] a null pointer [...]) [...] the behavior is undefined. Additionally the "searching and sorting" functions are specified as requiring valid pointer values as described in 7.1.4. This patch fixes the following sanitizer errors: block/qcow2.c:1807:41: runtime error: null pointer passed as argument 2, which is declared to never be null block/qcow2-cluster.c:86:26: runtime error: null pointer passed as argument 2, which is declared to never be null Reported-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-id: 1473758138-19260-1-git-send-email-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block/qcow2.c')
-rw-r--r--block/qcow2.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/block/qcow2.c b/block/qcow2.c
index c079aa83b6..0e53a4d666 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1804,7 +1804,10 @@ static size_t header_ext_add(char *buf, uint32_t magic, const void *s,
.magic = cpu_to_be32(magic),
.len = cpu_to_be32(len),
};
- memcpy(buf + sizeof(QCowExtension), s, len);
+
+ if (len) {
+ memcpy(buf + sizeof(QCowExtension), s, len);
+ }
return ext_len;
}