There's no point in allowing anything kernel internal nor procfs or sysfs. Reported-by: Zicheng Qu <quzicheng@xxxxxxxxxx> Link: https://lore.kernel.org/r/20250127091811.3183623-1-quzicheng@xxxxxxxxxx Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx> --- kernel/acct.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/kernel/acct.c b/kernel/acct.c index 48283efe8a12..6520baa13669 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -243,6 +243,20 @@ static int acct_on(struct filename *pathname) return -EACCES; } + /* Exclude kernel kernel internal filesystems. */ + if (file_inode(file)->i_sb->s_flags & (SB_NOUSER | SB_KERNMOUNT)) { + kfree(acct); + filp_close(file, NULL); + return -EINVAL; + } + + /* Exclude procfs and sysfs. */ + if (file_inode(file)->i_sb->s_iflags & SB_I_USERNS_VISIBLE) { + kfree(acct); + filp_close(file, NULL); + return -EINVAL; + } + if (!(file->f_mode & FMODE_CAN_WRITE)) { kfree(acct); filp_close(file, NULL); -- 2.47.2
