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fanotify_user: use upper_32_bits() to verify mask

PATCH In review Christian Brauner 2 participants 2 messages Mar 25, 2021

Subsystems (3)
VFS Fsnotify: filesystem notification infrastructure Fanotify
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Christian Brauner

author maintainer
#0 lore raw

PATCH 1/1 fanotify_user: use upper_32_bits() to verify mask

From: Christian Brauner <[email protected]>

I don't see an obvious reason why the upper 32 bit check needs to be open-coded this way. Switch to upper_32_bits() which is more idiomatic and should conceptually be the same check.

Cc Amir Goldstein <[email protected]>
Cc Jan Kara <[email protected]>
Signed-off-by Christian Brauner <[email protected]>
---
 fs/notify/fanotify/fanotify_user.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
fs/notify/fanotify/fanotify_user.c +1 -1
index 9e0c1afac8bd..d5683fa9d495 100644
@@ -1126,7 +1126,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 		 __func__, fanotify_fd, flags, dfd, pathname, mask);
 
 	/* we only use the lower 32 bits as of right now. */
-	if (mask & ((__u64)0xffffffff << 32))
+	if (upper_32_bits(mask))
 		return -EINVAL;
 
 	if (flags & ~FANOTIFY_MARK_FLAGS)

base-commit: 0d02ec6b3136c73c09e7859f0d0e4e2c4c07b49b

Signature · 1 line
2.27.0
maintainer
#1 lore raw
Quoted 9 lines · Christian Brauner

From: Christian Brauner <[email protected]>

I don't see an obvious reason why the upper 32 bit check needs to be open-coded this way. Switch to upper_32_bits() which is more idiomatic and should conceptually be the same check.

Cc Amir Goldstein <[email protected]>
Cc Jan Kara <[email protected]>
Signed-off-by Christian Brauner <[email protected]>

Thanks for the cleanup. I've added it to my tree.

Honza

Quoted 22 lines
---
 fs/notify/fanotify/fanotify_user.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
fs/notify/fanotify/fanotify_user.c +1 -1
index 9e0c1afac8bd..d5683fa9d495 100644
@@ -1126,7 +1126,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 		 __func__, fanotify_fd, flags, dfd, pathname, mask);
 
 	/* we only use the lower 32 bits as of right now. */
-	if (mask & ((__u64)0xffffffff << 32))
+	if (upper_32_bits(mask))
 		return -EINVAL;
 
 	if (flags & ~FANOTIFY_MARK_FLAGS)

base-commit: 0d02ec6b3136c73c09e7859f0d0e4e2c4c07b49b

Signature · 1 line
2.27.0
Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR