From: Michal Nazarewicz <mina86@xxxxxxxxxx>
blkcipher_walk_virt, blkcipher_walk_virt_block and
blkcipher_walk_phys functions modify the walk->flags by using
a binary “&=” or “|=” operator. This translate to read followed by
a write. However, the walk->flags is usually not initialised so the
read returns garbage.
At the same time, those functions call blkcipher_walk_first which
then calls blkcipher_walk_next function which zeroes all flags
except for BLKCIPHER_WALK_PHYS. This means, that the read done in
the virt, virt_block and phys functions is completely meaningless.
Dropping the read and changing “&=”/“|=” with a plain assignment
clears the confusion without changing any functionality of the API.
Signed-off-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
---
Admittedly, I'm not familiar with the crypto API, but I believe
this to be a valid change. This has actually been prompted by
Coverity scan which detects the read of initialised data.
crypto/blkcipher.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
index a79e7e9..3fb99d8 100644
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -305,7 +305,7 @@ static inline int blkcipher_copy_iv(struct blkcipher_walk *walk,
int blkcipher_walk_virt(struct blkcipher_desc *desc,
struct blkcipher_walk *walk)
{
- walk->flags &= ~BLKCIPHER_WALK_PHYS;
+ walk->flags = 0;
walk->blocksize = crypto_blkcipher_blocksize(desc->tfm);
return blkcipher_walk_first(desc, walk);
}
@@ -314,7 +314,7 @@ EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
int blkcipher_walk_phys(struct blkcipher_desc *desc,
struct blkcipher_walk *walk)
{
- walk->flags |= BLKCIPHER_WALK_PHYS;
+ walk->flags = BLKCIPHER_WALK_PHYS;
walk->blocksize = crypto_blkcipher_blocksize(desc->tfm);
return blkcipher_walk_first(desc, walk);
}
@@ -352,7 +352,7 @@ int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
unsigned int blocksize)
{
- walk->flags &= ~BLKCIPHER_WALK_PHYS;
+ walk->flags = 0;
walk->blocksize = blocksize;
return blkcipher_walk_first(desc, walk);
}
--
1.8.4
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