From f01a7898b77cee8ab455acd7bc9488e162286ee9 Mon Sep 17 00:00:00 2001 From: Eric Farman Date: Tue, 28 Jul 2026 05:30:13 +0200 Subject: [PATCH] s390/vfio_ccw: Free all memory if cp_init() fails ANBZ: #44670 commit 74186c2968f8f756ac3226b545b598457c910c75 upstream. The routine cp_free() is called to unpin/free any memory once an I/O is completed successfully, or if cp_prefetch() fails. But if cp_init() fails, and cp->initialized is not enabled, the same routine cannot be used to free all the memory. An attempt to address this exists in ccwchain_handle_ccw(), where a single call to ccwchain_free() is made for the currently-processed CCW segment. But this will leak other segments (created as a result of a Transfer in Channel) that had been allocated as part of the same channel program. Address this by performing the cleanup outside of the recursive ccwchain_handle_ccw()/ccwchain_loop_tic() logic. [backport-note] PatchPilot-Conflict-Type: context_drift PatchPilot-Conflict-Files: drivers/s390/cio/vfio_ccw_cp.c PatchPilot-Resolution: drivers/s390/cio/vfio_ccw_cp.c: Insert ccwchain_build_ccws() after ccwchain_loop_tic, keep downstream... Fixes: 8b515be512a2 ("vfio-ccw: Fix memory leak and don't call cp_free in cp_init") Cc: stable@vger.kernel.org Reviewed-by: Farhan Ali Reviewed-by: Matthew Rosato Signed-off-by: Eric Farman Signed-off-by: Christian Borntraeger Fixes: CVE-2026-80555 Assisted-by: PatchPilot Signed-off-by: Xunlei Pang --- drivers/s390/cio/vfio_ccw_cp.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index 8d1b2771c1aa..9186c0b7d223 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -453,9 +453,6 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp) /* Loop for tics on this new chain. */ ret = ccwchain_loop_tic(chain, cp); - if (ret) - ccwchain_free(chain); - return ret; } @@ -484,6 +481,23 @@ static int ccwchain_loop_tic(struct ccwchain *chain, struct channel_program *cp) return 0; } +static int ccwchain_build_ccws(u32 cda, struct channel_program *cp) +{ + struct ccwchain *chain, *temp; + int ret; + + ret = ccwchain_handle_ccw(cda, cp); + + if (ret) { + /* Cleanup if an error occurred */ + list_for_each_entry_safe(chain, temp, &cp->ccwchain_list, next) { + ccwchain_free(chain); + } + } + + return ret; +} + static int ccwchain_fetch_tic(struct ccwchain *chain, int idx, struct channel_program *cp) @@ -657,7 +671,7 @@ int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb) cp->mdev = mdev; /* Build a ccwchain for the first CCW segment */ - ret = ccwchain_handle_ccw(orb->cmd.cpa, cp); + ret = ccwchain_build_ccws(orb->cmd.cpa, cp); if (!ret) { cp->initialized = true; -- Gitee