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Fri, 26 Jun 2026 05:47:35 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 4DqOHXcSPmogbQAAD6G6ig (envelope-from ); Fri, 26 Jun 2026 05:47:35 +0000 Date: Fri, 26 Jun 2026 07:47:35 +0200 Message-ID: <87mrwhua2w.wl-tiwai@suse.de> From: Takashi Iwai To: Jiaming Zhang Cc: tiwai@suse.de, g@b4.vu, linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org, perex@perex.cz, syzkaller@googlegroups.com, tiwai@suse.com Subject: Re: [PATCH] ALSA: FCP: Fix NULL pointer dereference in interface lookup In-Reply-To: <20260625134933.425785-1-r772577952@gmail.com> References: <87echuvo7x.wl-tiwai@suse.de> <20260625134933.425785-1-r772577952@gmail.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/30.2 Mule/6.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-Spam-Flag: NO X-Rspamd-Action: no action X-Spam-Level: X-Spamd-Result: default: False [-3.51 / 50.00]; BAYES_HAM(-3.00)[99.99%]; MID_CONTAINS_FROM(1.00)[]; 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)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FREEMAIL_TO(0.00)[gmail.com]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FUZZY_RATELIMITED(0.00)[rspamd.com]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; RCVD_TLS_ALL(0.00)[]; DKIM_TRACE(0.00)[suse.de:+]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; DNSWL_BLOCKED(0.00)[2a07:de40:b281:106:10:150:64:167:received]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; RCPT_COUNT_SEVEN(0.00)[8]; RCVD_VIA_SMTP_AUTH(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:mid,suse.de:dkim,imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns] X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Rspamd-Queue-Id: C678A75ADA X-Spam-Score: -3.51 On Thu, 25 Jun 2026 15:49:33 +0200, Jiaming Zhang wrote: > > A malformed USB device can provide a vendor-specific interface without > any endpoint descriptors. fcp_find_fc_interface() currently selects the > first vendor-specific interface and reads endpoint 0 from it, without > checking whether the interface actually has any endpoints. > > When bNumEndpoints is zero, no endpoint array is allocated for the parsed > alternate setting, so get_endpoint(..., 0) yields an invalid endpoint > descriptor pointer. Dereferencing it through usb_endpoint_num() then > triggers a NULL pointer dereference. > > Skip vendor-specific interfaces that do not have any endpoints. > > Fixes: 46757a3e7d50 ("ALSA: FCP: Add Focusrite Control Protocol driver") > Reported-by: Jiaming Zhang > Closes: https://lore.kernel.org/lkml/CANypQFb1EHj0xX8bA1WxSOSK-5xca6ZNKzOQcp12=s=puY7VFw@mail.gmail.com/ > Signed-off-by: Jiaming Zhang Applied now. Thanks. Takashi