Messages in this thread Patch in this message |  | | From | Robert Garcia <> | | Subject | [PATCH 6.1.y] binfmt_misc: restore write access before closing files opened by open_exec() | | Date | Wed, 11 Mar 2026 10:06:29 +0800 |
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From: Zilin Guan <zilin@seu.edu.cn>
[ Upstream commit 90f601b497d76f40fa66795c3ecf625b6aced9fd ]
bm_register_write() opens an executable file using open_exec(), which internally calls do_open_execat() and denies write access on the file to avoid modification while it is being executed.
However, when an error occurs, bm_register_write() closes the file using filp_close() directly. This does not restore the write permission, which may cause subsequent write operations on the same file to fail.
Fix this by calling exe_file_allow_write_access() before filp_close() to restore the write permission properly.
Fixes: e7850f4d844e ("binfmt_misc: fix possible deadlock in bm_register_write") Signed-off-by: Zilin Guan <zilin@seu.edu.cn> Link: https://patch.msgid.link/20251105022923.1813587-1-zilin@seu.edu.cn Signed-off-by: Christian Brauner <brauner@kernel.org> [ Use allow_write_access() instead of exe_file_allow_write_access() according to commit 0357ef03c94ef ("fs: don't block write during exec on pre-content watched files"). ] Signed-off-by: Robert Garcia <rob_garcia@163.com> --- fs/binfmt_misc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c index 740dac1012ae..05c235309421 100644 --- a/fs/binfmt_misc.c +++ b/fs/binfmt_misc.c @@ -816,8 +816,10 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer, inode_unlock(d_inode(root)); if (err) { - if (f) + if (f) { + allow_write_access(f); filp_close(f, NULL); + } kfree(e); return err; } -- 2.34.1
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