Commit db77c789 authored by Gertjan Halkes's avatar Gertjan Halkes Committed by Greg Kroah-Hartman

9p: do not trust pdu content for stat item size

[ Upstream commit 2803cf43 ]

v9fs_dir_readdir() could deadloop if a struct was sent with a size set
to -2

Link: http://lkml.kernel.org/r/1536134432-11997-1-git-send-email-asmadeus@codewreck.org
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88021Signed-off-by: default avatarGertjan Halkes <gertjan@google.com>
Signed-off-by: default avatarDominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent f9368366
......@@ -105,7 +105,6 @@ static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx)
int err = 0;
struct p9_fid *fid;
int buflen;
int reclen = 0;
struct p9_rdir *rdir;
struct kvec kvec;
......@@ -138,11 +137,10 @@ static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx)
while (rdir->head < rdir->tail) {
err = p9stat_read(fid->clnt, rdir->buf + rdir->head,
rdir->tail - rdir->head, &st);
if (err) {
if (err <= 0) {
p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
return -EIO;
}
reclen = st.size+2;
over = !dir_emit(ctx, st.name, strlen(st.name),
v9fs_qid2ino(&st.qid), dt_type(&st));
......@@ -150,8 +148,8 @@ static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx)
if (over)
return 0;
rdir->head += reclen;
ctx->pos += reclen;
rdir->head += err;
ctx->pos += err;
}
}
}
......
......@@ -571,9 +571,10 @@ int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
if (ret) {
p9_debug(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
trace_9p_protocol_dump(clnt, &fake_pdu);
return ret;
}
return ret;
return fake_pdu.offset;
}
EXPORT_SYMBOL(p9stat_read);
......
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