The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x dc30c011469165d57af9adac5baff7d767d20e5c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023041103-fading-coexist-fbc0@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: dc30c0114691 ("drm/i915: fix race condition UAF in i915_perf_add_config_ioctl") 2fec539112e8 ("i915/perf: Replace DRM_DEBUG with driver specific drm_dbg call") 046d1660daee ("drm/i915/gem: Return an error ptr from context_lookup") a4839cb1137b ("drm/i915: Stop manually RCU banging in reset_stats_ioctl (v2)") 651e7d48577a ("drm/i915: replace IS_GEN and friends with GRAPHICS_VER") ec2b1485a065 ("drm/i915/dmc: s/HAS_CSR/HAS_DMC") c24760cf42c3 ("drm/i915/dmc: s/intel_csr/intel_dmc") 93e7e61eb448 ("drm/i915/display: rename display version macros") 4df9c1ae7a4b ("drm/i915: rename display.version to display.ver") 6c51f288b41f ("drm/i915: Don't use {skl, cnl}_hpd_pin() for bxt/glk") 0fe6637d9852 ("drm/i915: Restore lost glk ccs w/a") 87b8c3bc8d27 ("drm/i915: Restore lost glk FBC 16bpp w/a") 2446e1d6433b ("drm/i915/display: Eliminate IS_GEN9_{BC,LP}") 9c0fed84d575 ("Merge tag 'drm-intel-next-2021-04-01' of git://anongit.freedesktop.org/drm/drm-intel into drm-next") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From dc30c011469165d57af9adac5baff7d767d20e5c Mon Sep 17 00:00:00 2001 From: Min Li <lm0963hack@xxxxxxxxx> Date: Tue, 28 Mar 2023 17:36:27 +0800 Subject: [PATCH] drm/i915: fix race condition UAF in i915_perf_add_config_ioctl Userspace can guess the id value and try to race oa_config object creation with config remove, resulting in a use-after-free if we dereference the object after unlocking the metrics_lock. For that reason, unlocking the metrics_lock must be done after we are done dereferencing the object. Signed-off-by: Min Li <lm0963hack@xxxxxxxxx> Fixes: f89823c21224 ("drm/i915/perf: Implement I915_PERF_ADD/REMOVE_CONFIG interface") Cc: <stable@xxxxxxxxxxxxxxx> # v4.14+ Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx> Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@xxxxxxxxx> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20230328093627.5067-1-lm0963hack@xxxxxxxxx [tursulin: Manually added stable tag.] (cherry picked from commit 49f6f6483b652108bcb73accd0204a464b922395) Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c index 283a4a3c6862..004074936300 100644 --- a/drivers/gpu/drm/i915/i915_perf.c +++ b/drivers/gpu/drm/i915/i915_perf.c @@ -4638,13 +4638,13 @@ int i915_perf_add_config_ioctl(struct drm_device *dev, void *data, err = oa_config->id; goto sysfs_err; } - - mutex_unlock(&perf->metrics_lock); + id = oa_config->id; drm_dbg(&perf->i915->drm, "Added config %s id=%i\n", oa_config->uuid, oa_config->id); + mutex_unlock(&perf->metrics_lock); - return oa_config->id; + return id; sysfs_err: mutex_unlock(&perf->metrics_lock);
