From: Al Viro viro@zeniv.linux.org.uk

stable inclusion from stable-v4.19.319 commit ed42e8ff509d2a61c6642d1825032072dab79f26 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAKPUO CVE: CVE-2024-42265

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=t...

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commit 8aa37bde1a7b645816cda8b80df4753ecf172bf1 upstream.

both callers have verified that fd is not greater than ->max_fds; however, misprediction might end up with tofree = fdt->fd[fd]; being speculatively executed. That's wrong for the same reasons why it's wrong in close_fd()/file_close_fd_locked(); the same solution applies - array_index_nospec(fd, fdt->max_fds) could differ from fd only in case of speculative execution on mispredicted path.

Cc: stable@vger.kernel.org Signed-off-by: Al Viro viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Long Li leo.lilong@huawei.com --- fs/file.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/fs/file.c b/fs/file.c index b5df6680301c..4c192bc68494 100644 --- a/fs/file.c +++ b/fs/file.c @@ -978,6 +978,7 @@ __releases(&files->file_lock) * tables and this condition does not arise without those. */ fdt = files_fdtable(files); + fd = array_index_nospec(fd, fdt->max_fds); tofree = fdt->fd[fd]; if (!tofree && fd_is_open(fd, fdt)) { err = -EBUSY;