From cf01f4eef9fe367ec0d85b38dd7214e29e376cdb Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Fri, 9 May 2014 11:41:54 -0400 Subject: [PATCH] locks: only validate the lock vs. f_mode in F_SETLK codepaths v2: replace missing break in switch statement (as pointed out by Dave Jones) commit bce7560d4946 (locks: consolidate checks for compatible filp->f_mode values in setlk handlers) introduced a regression in the F_GETLK handler. flock64_to_posix_lock is a shared codepath between F_GETLK and F_SETLK, but the f_mode checks should only be applicable to the F_SETLK codepaths according to POSIX. Instead of just reverting the patch, add a new function to do this checking and have the F_SETLK handlers call it. Cc: Dave Jones Reported-and-Tested-by: Reuben Farrelly Signed-off-by: Jeff Layton --- fs/locks.c | 36 ++++++++++++++++++++++++------------ 1 file changed, 24 insertions(+), 12 deletions(-) diff --git a/fs/locks.c b/fs/locks.c index e663aeac579e..e390bd9ae068 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -389,18 +389,6 @@ static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, fl->fl_ops = NULL; fl->fl_lmops = NULL; - /* Ensure that fl->fl_filp has compatible f_mode */ - switch (l->l_type) { - case F_RDLCK: - if (!(filp->f_mode & FMODE_READ)) - return -EBADF; - break; - case F_WRLCK: - if (!(filp->f_mode & FMODE_WRITE)) - return -EBADF; - break; - } - return assign_type(fl, l->l_type); } @@ -2034,6 +2022,22 @@ static int do_lock_file_wait(struct file *filp, unsigned int cmd, return error; } +/* Ensure that fl->fl_filp has compatible f_mode for F_SETLK calls */ +static int +check_fmode_for_setlk(struct file_lock *fl) +{ + switch (fl->fl_type) { + case F_RDLCK: + if (!(fl->fl_file->f_mode & FMODE_READ)) + return -EBADF; + break; + case F_WRLCK: + if (!(fl->fl_file->f_mode & FMODE_WRITE)) + return -EBADF; + } + return 0; +} + /* Apply the lock described by l to an open file descriptor. * This implements both the F_SETLK and F_SETLKW commands of fcntl(). */ @@ -2071,6 +2075,10 @@ again: if (error) goto out; + error = check_fmode_for_setlk(file_lock); + if (error) + goto out; + /* * If the cmd is requesting file-private locks, then set the * FL_OFDLCK flag and override the owner. @@ -2206,6 +2214,10 @@ again: if (error) goto out; + error = check_fmode_for_setlk(file_lock); + if (error) + goto out; + /* * If the cmd is requesting file-private locks, then set the * FL_OFDLCK flag and override the owner. -- 2.20.1