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author | 2021-12-03 12:17:00 +0100 | |
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committer | 2021-12-03 18:50:28 +0100 | |
commit | 476860b3eb4a50958243158861d5340066df5af2 (patch) | |
tree | 4673772f88d7c7ba3580500331ce60eaa21c1b4d /include/linux/fs.h | |
parent | fs: move mapping helpers (diff) | |
download | linux-476860b3eb4a50958243158861d5340066df5af2.tar.gz linux-476860b3eb4a50958243158861d5340066df5af2.tar.bz2 linux-476860b3eb4a50958243158861d5340066df5af2.zip |
fs: tweak fsuidgid_has_mapping()
If the caller's fs{g,u}id aren't mapped in the mount's idmapping we can
return early and skip the check whether the mapped fs{g,u}id also have a
mapping in the filesystem's idmapping. If the fs{g,u}id aren't mapped in
the mount's idmapping they consequently can't be mapped in the
filesystem's idmapping. So there's no point in checking that.
Link: https://lore.kernel.org/r/20211123114227.3124056-4-brauner@kernel.org (v1)
Link: https://lore.kernel.org/r/20211130121032.3753852-4-brauner@kernel.org (v2)
Link: https://lore.kernel.org/r/20211203111707.3901969-4-brauner@kernel.org
Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
CC: linux-fsdevel@vger.kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Seth Forshee <sforshee@digitalocean.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Diffstat (limited to 'include/linux/fs.h')
-rw-r--r-- | include/linux/fs.h | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index b3bcb2129699..db5ee15e36b1 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1695,10 +1695,18 @@ static inline void inode_fsgid_set(struct inode *inode, static inline bool fsuidgid_has_mapping(struct super_block *sb, struct user_namespace *mnt_userns) { - struct user_namespace *s_user_ns = sb->s_user_ns; + struct user_namespace *fs_userns = sb->s_user_ns; + kuid_t kuid; + kgid_t kgid; - return kuid_has_mapping(s_user_ns, mapped_fsuid(mnt_userns)) && - kgid_has_mapping(s_user_ns, mapped_fsgid(mnt_userns)); + kuid = mapped_fsuid(mnt_userns); + if (!uid_valid(kuid)) + return false; + kgid = mapped_fsgid(mnt_userns); + if (!gid_valid(kgid)) + return false; + return kuid_has_mapping(fs_userns, kuid) && + kgid_has_mapping(fs_userns, kgid); } extern struct timespec64 current_time(struct inode *inode); |