Zilin Guan e785f552ab binfmt_misc: restore write access before closing files opened by open_exec() ...

[ Upstream commit 90f601b497 ]

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: e7850f4d84 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

2025-11-24 10:37:37 +01:00

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