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ext4: report correct st_size for encrypted symlinks 

BugLink: https://bugs.launchpad.net/bugs/1945517

commit 8c4bca10ce upstream.

The stat() family of syscalls report the wrong size for encrypted
symlinks, which has caused breakage in several userspace programs.

Fix this by calling fscrypt_symlink_getattr() after ext4_getattr() for
encrypted symlinks.  This function computes the correct size by reading
and decrypting the symlink target (if it's not already cached).

For more details, see the commit which added fscrypt_symlink_getattr().

Fixes: f348c25232 ("ext4 crypto: add symlink encryption")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210702065350.209646-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
This commit is contained in:
Eric Biggers 2021-09-01 09:40:39 -07:00 committed by Stefan Bader
parent a2fe5aca77
commit 6cf4e2935e
1 changed files with 10 additions and 1 deletions
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11
fs/ext4/symlink.c
View File

@ -52,10 +52,19 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry,
return paddr;
}
static int ext4_encrypted_symlink_getattr(const struct path *path,
struct kstat *stat, u32 request_mask,
unsigned int query_flags)
{
ext4_getattr(path, stat, request_mask, query_flags);
return fscrypt_symlink_getattr(path, stat);
}
const struct inode_operations ext4_encrypted_symlink_inode_operations = {
.get_link = ext4_encrypted_get_link,
.setattr = ext4_setattr,
.getattr = ext4_getattr,
.getattr = ext4_encrypted_symlink_getattr,
.listxattr = ext4_listxattr,
};