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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Action: no action X-Rspamd-Queue-Id: 055E7759F2 X-Spam-Flag: NO X-Spam-Score: -4.51 X-Spam-Level: X-Spamd-Result: default: False [-4.51 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; FUZZY_RATELIMITED(0.00)[rspamd.com]; MIME_TRACE(0.00)[0:+]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; ARC_NA(0.00)[]; FREEMAIL_TO(0.00)[stu.xidian.edu.cn,linux.intel.com,kernel.org,gmail.com,ffwll.ch]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; DKIM_TRACE(0.00)[suse.de:+]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCVD_TLS_ALL(0.00)[]; DNSWL_BLOCKED(0.00)[2a07:de40:b281:104:10:150:64:97:from]; RCPT_COUNT_SEVEN(0.00)[7]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; DBL_BLOCKED_OPENRESOLVER(0.00)[intel.com:email,lists.freedesktop.org:email,ffwll.ch:email,suse.com:url,bootlin.com:url,xidian.edu.cn:email,suse.de:dkim,suse.de:email,suse.de:mid] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org Hi Am 05.06.26 um 05:06 schrieb 王明煜: > Hi maintainers, > > Just a gentle ping on this patch. It fixes a WARN triggered during fuzzing when negative user handles are passed. > > Please let me know if it needs any revisions or if there is anything else I can do to help move it forward. > > Thanks, > Mingyu > > >> -----原始邮件----- >> 发件人: "Mingyu Wang" <25181214217@stu.xidian.edu.cn> >> 发送时间:2026-04-22 19:42:47 (星期三) >> 收件人: maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch >> 抄送: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, "Mingyu Wang" <25181214217@stu.xidian.edu.cn> >> 主题: [PATCH] drm/gem: fix warning in idr_alloc due to unvalidated user handle >> >> During fuzzing, a warning was triggered in idr_alloc() when handling >> the DRM_IOCTL_GEM_CHANGE_HANDLE (or similar) ioctl. >> >> The function drm_gem_change_handle_ioctl() currently only checks if >> args->new_handle is strictly greater than INT_MAX. However, it fails >> to check for negative values. If a userpace application passes a >> negative handle, it bypasses the upper-bound check and is passed >> directly to idr_alloc() as the 'start' parameter, triggering the >> WARN_ON_ONCE(start < 0) inside idr_alloc(). args->new_handle is unsigned.  IIRC, for the test, INT_MAX should be interpreted as unsigned as well. So how can it get across the INT_MAX test? There's an explicit cast to int at [1], which might have an effect here. Does it work of you explicitly cast INT_MAX to u32 in that test? I'm also worried about interpreting the handle as signed and then adding +1 to it. [2]  idr_alloc() appears to handle it gracefully, [3] but it still looks fishy. [1] https://elixir.bootlin.com/linux/v7.0.11/source/include/vdso/limits.h#L8 [2] https://elixir.bootlin.com/linux/v7.0.11/source/drivers/gpu/drm/drm_gem.c#L1033 [3] https://elixir.bootlin.com/linux/v7.0.11/source/lib/idr.c#L89 Best regards Thomas >> >> Fix this by explicitly validating that the user-provided handle is >> strictly positive and within the valid IDR range. >> >> Signed-off-by: Mingyu Wang <25181214217@stu.xidian.edu.cn> >> --- >> drivers/gpu/drm/drm_gem.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c >> index d6424267260b..3d84d4f1c3e0 100644 >> --- a/drivers/gpu/drm/drm_gem.c >> +++ b/drivers/gpu/drm/drm_gem.c >> @@ -1026,7 +1026,7 @@ int drm_gem_change_handle_ioctl(struct drm_device *dev, void *data, >> return -EOPNOTSUPP; >> >> /* idr_alloc() limitation. */ >> - if (args->new_handle > INT_MAX) >> + if (args->new_handle <= 0 || args->new_handle > INT_MAX) >> return -EINVAL; >> handle = args->new_handle; >> >> -- >> 2.34.1 -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)