[PATCH master] fs: smhfs: fix crash when stat'ing file

[PATCH master] fs: smhfs: fix crash when stat'ing file

[Ahmad Fatoum]

Starting with commit 7d91d564361e ("fs: replace FILE.size by f_inode.i_size"),
struct file no longer had a size member, but instead the inode's i_size
member is used. The inode is populated by the file system core when a
file is first opened.

However, the semihosting file system creates a fake struct file to pass
to smhfs_open, which duly fails, because the inode member is
uninitialized.

Fix this for now, by faking an allocated inode as well.

The better fix would be switching to a non-legacy file system, but
that (remain)s a quest for another day.

Fixes: 7d91d564361e ("fs: replace FILE.size by f_inode.i_size")
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 fs/smhfs.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/smhfs.c b/fs/smhfs.c
index e0e98f5213e9..3a3b4bdc1d94 100644
--- a/fs/smhfs.c
+++ b/fs/smhfs.c
@@ -114,12 +114,16 @@ static int smhfs_stat(struct device __always_unused *dev,
 {
 	struct file file;
 
+	file.f_inode = xzalloc(sizeof(*file.f_inode));
+
 	if (smhfs_open(NULL, &file, filename) == 0) {
 		s->st_mode = S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO;
 		s->st_size = file.f_size;
 	}
 	smhfs_close(NULL, &file);
 
+	free(file.f_inode);
+
 	return 0;
 }
 
-- 
2.39.5

Re: [PATCH master] fs: smhfs: fix crash when stat'ing file

[Sascha Hauer]

On Wed, 26 Mar 2025 17:59:49 +0100, Ahmad Fatoum wrote:
> Starting with commit 7d91d564361e ("fs: replace FILE.size by f_inode.i_size"),
> struct file no longer had a size member, but instead the inode's i_size
> member is used. The inode is populated by the file system core when a
> file is first opened.
> 
> However, the semihosting file system creates a fake struct file to pass
> to smhfs_open, which duly fails, because the inode member is
> uninitialized.
> 
> [...]

Applied, thanks!

[1/1] fs: smhfs: fix crash when stat'ing file
      https://git.pengutronix.de/cgit/barebox/commit/?id=3c57263db03b (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>