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authorChristoph Hellwig <hch@lst.de>2020-05-08 08:55:03 +0200
committerChristoph Hellwig <hch@lst.de>2020-07-08 08:27:56 +0200
commita01ac27be4729f80176a45c54611b768dfbdc840 (patch)
treea16940d89cd9a69f4119cd29fc80f4e0018fd2ec /fs/read_write.c
parent9db97752244919c604eb21df7ef2da3bf58aec73 (diff)
fs: check FMODE_WRITE in __kernel_write
Add a WARN_ON_ONCE if the file isn't actually open for write. This matches the check done in vfs_write, but actually warn warns as a kernel user calling write on a file not opened for writing is a pretty obvious programming error. Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index 2c601d853ff3..8f9fc05990ae 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -505,6 +505,8 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t
const char __user *p;
ssize_t ret;
+ if (WARN_ON_ONCE(!(file->f_mode & FMODE_WRITE)))
+ return -EBADF;
if (!(file->f_mode & FMODE_CAN_WRITE))
return -EINVAL;