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author | J. Bruce Fields <bfields@citi.umich.edu> | 2007-03-20 22:50:12 +0100 |
---|---|---|
committer | Herbert Xu <herbert@gondor.apana.org.au> | 2007-03-20 22:50:12 +0100 |
commit | f70ee5ec8fc59ba2d905e6daf0d395edf6fb461d (patch) | |
tree | bfa4a0f71f0e11187775f5f8c53e2a8afbb673ce /crypto | |
parent | [PATCH] Fix build error due to not including <linux/errno.h> (diff) | |
download | linux-f70ee5ec8fc59ba2d905e6daf0d395edf6fb461d.tar.xz linux-f70ee5ec8fc59ba2d905e6daf0d395edf6fb461d.zip |
[CRYPTO] api: scatterwalk_copychunks() fails to advance through scatterlist
In the loop in scatterwalk_copychunks(), if walk->offset is zero,
then scatterwalk_pagedone rounds that up to the nearest page boundary:
walk->offset += PAGE_SIZE - 1;
walk->offset &= PAGE_MASK;
which is a no-op in this case, so we don't advance to the next element
of the scatterlist array:
if (walk->offset >= walk->sg->offset + walk->sg->length)
scatterwalk_start(walk, sg_next(walk->sg));
and we end up copying the same data twice.
It appears that other callers of scatterwalk_{page}done first advance
walk->offset, so I believe that's the correct thing to do here.
This caused a bug in NFS when run with krb5p security, which would
cause some writes to fail with permissions errors--for example, writes
of less than 8 bytes (the des blocksize) at the start of a file.
A git-bisect shows the bug was originally introduced by
5c64097aa0f6dc4f27718ef47ca9a12538d62860, first in 2.6.19-rc1.
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
-rw-r--r-- | crypto/scatterwalk.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c index 35172d3f043b..a66423121773 100644 --- a/crypto/scatterwalk.c +++ b/crypto/scatterwalk.c @@ -91,6 +91,8 @@ void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, memcpy_dir(buf, vaddr, len_this_page, out); scatterwalk_unmap(vaddr, out); + scatterwalk_advance(walk, nbytes); + if (nbytes == len_this_page) break; @@ -99,7 +101,5 @@ void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, scatterwalk_pagedone(walk, out, 1); } - - scatterwalk_advance(walk, nbytes); } EXPORT_SYMBOL_GPL(scatterwalk_copychunks); |