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| author | Robin Murphy <robin.murphy@arm.com> | 2020-01-17 15:48:39 +0000 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-01-17 16:05:50 +0000 |
| commit | c2c24edb1d9c308011f5a1328563d8da8c92c849 (patch) | |
| tree | 2b2438f62417db3238cb88b111fe24120fab8880 /arch/arm64/lib | |
| parent | 5777eaed566a1d63e344d3dd8f2b5e33be20643e (diff) | |
| download | lwn-c2c24edb1d9c308011f5a1328563d8da8c92c849.tar.gz lwn-c2c24edb1d9c308011f5a1328563d8da8c92c849.zip | |
arm64: csum: Fix pathological zero-length calls
In validating the checksumming results of the new routine, I sadly
neglected to test its not-checksumming results. Thus it slipped through
that the one case where @buff is already dword-aligned and @len = 0
manages to defeat the tail-masking logic and behave as if @len = 8.
For a zero length it doesn't make much sense to deference @buff anyway,
so just add an early return (which has essentially zero impact on
performance).
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/lib')
| -rw-r--r-- | arch/arm64/lib/csum.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm64/lib/csum.c b/arch/arm64/lib/csum.c index 847eb725ce09..1f82c66b32ea 100644 --- a/arch/arm64/lib/csum.c +++ b/arch/arm64/lib/csum.c @@ -20,6 +20,9 @@ unsigned int do_csum(const unsigned char *buff, int len) const u64 *ptr; u64 data, sum64 = 0; + if (unlikely(len == 0)) + return 0; + offset = (unsigned long)buff & 7; /* * This is to all intents and purposes safe, since rounding down cannot |