From 8e5389132ab429604c1a2459b52f0c849a71cc61 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Sat, 20 Mar 2021 13:26:23 +0100 Subject: fs: introduce fsuidgid_has_mapping() helper Don't open-code the checks and instead move them into a clean little helper we can call. This also reduces the risk that if we ever change something we forget to change all locations. Link: https://lore.kernel.org/r/20210320122623.599086-4-christian.brauner@ubuntu.com Inspired-by: Vivek Goyal Cc: Christoph Hellwig Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- include/linux/fs.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index e34967829183..e9e7e799425e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1692,6 +1692,26 @@ static inline kgid_t mapped_fsgid(struct user_namespace *mnt_userns) return kgid_from_mnt(mnt_userns, current_fsgid()); } +/** + * fsuidgid_has_mapping() - check whether caller's fsuid/fsgid is mapped + * @sb: the superblock we want a mapping in + * @mnt_userns: user namespace of the relevant mount + * + * Check whether the caller's fsuid and fsgid have a valid mapping in the + * s_user_ns of the superblock @sb. If the caller is on an idmapped mount map + * the caller's fsuid and fsgid according to the @mnt_userns first. + * + * Return: true if fsuid and fsgid is mapped, false if not. + */ +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; + + return kuid_has_mapping(s_user_ns, mapped_fsuid(mnt_userns)) && + kgid_has_mapping(s_user_ns, mapped_fsgid(mnt_userns)); +} + extern struct timespec64 current_time(struct inode *inode); /* -- cgit v1.2.3