From: Nicholas Carlini Date: Fri, 27 Mar 2026 02:18:23 +0000 (+0000) Subject: io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check X-Git-Tag: v7.0-rc6~27^2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5170efd9c344c68a8075dcb8ed38d3f8a60e7ed4;p=thirdparty%2Flinux.git io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check __io_uring_show_fdinfo() iterates over pending SQEs and, for 128-byte SQEs on an IORING_SETUP_SQE_MIXED ring, needs to detect when the second half of the SQE would be past the end of the sq_sqes array. The current check tests (++sq_head & sq_mask) == 0, but sq_head is only incremented when a 128-byte SQE is encountered, not on every iteration. The actual array index is sq_idx = (i + sq_head) & sq_mask, which can be sq_mask (the last slot) while the wrap check passes. Fix by checking sq_idx directly. Keep the sq_head increment so the loop still skips the second half of the 128-byte SQE on the next iteration. Fixes: 1cba30bf9fdd ("io_uring: add support for IORING_SETUP_SQE_MIXED") Signed-off-by: Nicholas Carlini Link: https://patch.msgid.link/20260327021823.3138396-1-nicholas@carlini.com Signed-off-by: Jens Axboe --- diff --git a/io_uring/fdinfo.c b/io_uring/fdinfo.c index 25c92ace18bd..c2d3e45544bb 100644 --- a/io_uring/fdinfo.c +++ b/io_uring/fdinfo.c @@ -119,12 +119,13 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) sq_idx); break; } - if ((++sq_head & sq_mask) == 0) { + if (sq_idx == sq_mask) { seq_printf(m, "%5u: corrupted sqe, wrapping 128B entry\n", sq_idx); break; } + sq_head++; i++; sqe128 = true; }