Hi,
Coverity complains about the new ext4 crypto code. The complaint is that
ext4_fname_crypto_alloc_buffer() and ext4_fname_crypto_namelen_on_disk()
check for ctx being NULL but they dereference it before that check.
I've checked and didn't find callers that would actually pass NULL into
these functions so do we want to remove the unused check or move the
dereference? I think it would be worth cleaning up just that we don't fall
into the trap sometime later...
Honza
----- Forwarded message from scan-admin@xxxxxxxxxxxx -----
** CID 1296585: Null pointer dereferences (REVERSE_INULL)
/fs/ext4/crypto_fname.c: 500 in ext4_fname_crypto_alloc_buffer()
________________________________________________________________________________________________________
*** CID 1296585: Null pointer dereferences (REVERSE_INULL)
/fs/ext4/crypto_fname.c: 500 in ext4_fname_crypto_alloc_buffer()
494 int ext4_fname_crypto_alloc_buffer(struct ext4_fname_crypto_ctx *ctx,
495 u32 ilen, struct ext4_str *crypto_str)
496 {
497 unsigned int olen;
498 int padding = 4 << (ctx->flags & EXT4_POLICY_FLAGS_PAD_MASK);
499
>>> CID 1296585: Null pointer dereferences (REVERSE_INULL)
>>> Null-checking "ctx" suggests that it may be null, but it has already been dereferenced on all paths leading to the check.
500 if (!ctx)
501 return -EIO;
502 if (padding < EXT4_CRYPTO_BLOCK_SIZE)
503 padding = EXT4_CRYPTO_BLOCK_SIZE;
504 olen = ext4_fname_crypto_round_up(ilen, padding);
505 crypto_str->len = olen;
** CID 1296586: Null pointer dereferences (REVERSE_INULL)
/fs/ext4/crypto_fname.c: 476 in ext4_fname_crypto_namelen_on_disk()
________________________________________________________________________________________________________
*** CID 1296586: Null pointer dereferences (REVERSE_INULL)
/fs/ext4/crypto_fname.c: 476 in ext4_fname_crypto_namelen_on_disk()
470 int ext4_fname_crypto_namelen_on_disk(struct ext4_fname_crypto_ctx *ctx,
471 u32 namelen)
472 {
473 u32 ciphertext_len;
474 int padding = 4 << (ctx->flags & EXT4_POLICY_FLAGS_PAD_MASK);
475
>>> CID 1296586: Null pointer dereferences (REVERSE_INULL)
>>> Null-checking "ctx" suggests that it may be null, but it has already been dereferenced on all paths leading to the check.
476 if (ctx == NULL)
477 return -EIO;
478 if (!(ctx->has_valid_key))
479 return -EACCES;
480 ciphertext_len = (namelen < EXT4_CRYPTO_BLOCK_SIZE) ?
481 EXT4_CRYPTO_BLOCK_SIZE : namelen;
________________________________________________________________________________________________________
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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