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authorEric Biggers <ebiggers@kernel.org>2025-10-11 18:57:34 -0700
committerSteve French <stfrench@microsoft.com>2025-10-15 22:10:28 -0500
commitae04b1bb06f8c1738d01dc2f9b9391c4480544e4 (patch)
treefe414feb63d02de99f19cbc1ac9b68feba370145
parente05b3115e75381369be84abe5d46565ce0fcedc8 (diff)
smb: client: Use MD5 library for M-F symlink hashing
Convert parse_mf_symlink() and format_mf_symlink() to use the MD5 library instead of a "md5" crypto_shash. This is simpler and faster. With the library there's no need to allocate memory, no need to handle errors, and the MD5 code is accessed directly without inefficient indirect calls and other unnecessary API overhead. This also fixes an issue where these functions did not work on kernels booted in FIPS mode. The use of MD5 here is for data integrity rather than a security purpose, so it can use a non-FIPS-approved algorithm. Reviewed-by: Stefan Metzmacher <metze@samba.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
-rw-r--r--fs/smb/client/Kconfig1
-rw-r--r--fs/smb/client/link.c31
2 files changed, 4 insertions, 28 deletions
diff --git a/fs/smb/client/Kconfig b/fs/smb/client/Kconfig
index f0c1ff8544f6..f5a980bdfc93 100644
--- a/fs/smb/client/Kconfig
+++ b/fs/smb/client/Kconfig
@@ -16,6 +16,7 @@ config CIFS
select CRYPTO_ECB
select CRYPTO_AES
select CRYPTO_LIB_ARC4
+ select CRYPTO_LIB_MD5
select CRYPTO_LIB_SHA256
select CRYPTO_LIB_SHA512
select KEYS
diff --git a/fs/smb/client/link.c b/fs/smb/client/link.c
index fe80e711cd75..70f3c0c67eeb 100644
--- a/fs/smb/client/link.c
+++ b/fs/smb/client/link.c
@@ -5,6 +5,7 @@
* Author(s): Steve French (sfrench@us.ibm.com)
*
*/
+#include <crypto/md5.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/slab.h>
@@ -37,23 +38,6 @@
#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) md5_hash
static int
-symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
-{
- int rc;
- struct shash_desc *md5 = NULL;
-
- rc = cifs_alloc_hash("md5", &md5);
- if (rc)
- return rc;
-
- rc = crypto_shash_digest(md5, link_str, link_len, md5_hash);
- if (rc)
- cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
- cifs_free_hash(&md5);
- return rc;
-}
-
-static int
parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
char **_link_str)
{
@@ -77,11 +61,7 @@ parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
return -EINVAL;
- rc = symlink_hash(link_len, link_str, md5_hash);
- if (rc) {
- cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
- return rc;
- }
+ md5(link_str, link_len, md5_hash);
scnprintf(md5_str2, sizeof(md5_str2),
CIFS_MF_SYMLINK_MD5_FORMAT,
@@ -103,7 +83,6 @@ parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
static int
format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
{
- int rc;
unsigned int link_len;
unsigned int ofs;
u8 md5_hash[16];
@@ -116,11 +95,7 @@ format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
return -ENAMETOOLONG;
- rc = symlink_hash(link_len, link_str, md5_hash);
- if (rc) {
- cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
- return rc;
- }
+ md5(link_str, link_len, md5_hash);
scnprintf(buf, buf_len,
CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,