From patchwork Wed Dec 4 16:26:19 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jann Horn X-Patchwork-Id: 13894071 Received: from mail-wm1-f52.google.com (mail-wm1-f52.google.com [209.85.128.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 81C28156962 for ; Wed, 4 Dec 2024 16:27:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.52 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733329625; cv=none; b=FjKHi1KlbprzeflbfAACYGWQtppIHhUnaWFET+hAFW+4nHJCTwpH7/b5R4dsWgL2nXGL8jeDS/W0ySPiEmq43C7SWrg6HfHrs4osFKsVkNY/53JnjTzkPgfRRnH4K20JqcrLnzBJWbLVy1sbWtvdYLrQnG7WPmzeb2d6pxrY118= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733329625; c=relaxed/simple; bh=Tb4zTg8gwUbDaogCnGrqjqwGKOpD1jahUvTB+lbqtzQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=CVaxgYaSGdpQYK3ielyZ7S+Grf0KyLWa1hWFUENIJqu38Tc5vL4UbMYFBppEH94Tx9sXGG/9RXyrI3azySngGT6Rm2devTpYJ4YwAHWtllG76/VlEAuIAWyRkT1J9XpiYc3Y/Td0rHblwsigeyL6ClV2+9YB1feONPSLUsoVuc8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=nHtWyHxu; arc=none smtp.client-ip=209.85.128.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="nHtWyHxu" Received: by mail-wm1-f52.google.com with SMTP id 5b1f17b1804b1-434a9f9a225so60215e9.1 for ; Wed, 04 Dec 2024 08:27:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1733329621; x=1733934421; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=G9G1+IA4HE6z5Jl984QuG0eTi6gYVIS+JAIiJpGUT64=; b=nHtWyHxuXQRjOMdNrhEB6NLoK3rnkKQbbuBVs9TqL3+5rdKYuiAzoaG+vv508D/rfB UoJGmSYPjwXmsBGamgihduaUltJIpDcRgY/r9rV2wGxgTsZH40yPJPa3pJpUxc37rky1 U6bTdxGhky8+oHiClGs2maV725B3l/+fm+6+RCiKt31IqGU7HRlG7+QP7rULXgFzXDbL exWO6ALc2aAwu3YKMwGeX6c5uqnDGK++9DVz/uUepkrwhD0egCEU2x1EI3qUTRe+t8Hk rHuRvAgTD6guaSlBsGyWfWUmJxJ+9nMPiRhe7WhHFoVX30SGZsb/x7fKqEDWvi1bl2Fo 08hw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733329621; x=1733934421; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=G9G1+IA4HE6z5Jl984QuG0eTi6gYVIS+JAIiJpGUT64=; b=AlPFozZaulcl6KnoeNTmow/iEJiVhlYkqx4+eChW9VymcnlYD/DgHvZcNmHHWrA3pd +iMEpAsAgVbzdNtY89kuHWGVjJNdD4FHjGttbtj7PSnAB6+ZKiP64MdNfoxwMkv4YN4V 7olIRoeYrGLKT6vO2P1gPY0tKJyAfAyf4wILwamy+RxM98eLMJyt/FXN01Q+kHF3hfoa i5cGE3gmYWeRwLdC3p4mgQH4TRcNYbloMVXjHJ5/isdGagvjb2m8TT2JukQfL3HHyvXS qwwA81FRUQ1eg3dB2Bx8dOaQ/rvFEfwv82BuAncRg0mfkJVyu3ti8NIFP52VUg+vhemk Tx3Q== X-Forwarded-Encrypted: i=1; AJvYcCXrd1E4tzWVetmiSmGyKOE2i5R/rj+vMUN20SWK+d3572qeBkYCOYztck9qdue/7MPwP17XFNe0833QzQ==@vger.kernel.org X-Gm-Message-State: AOJu0Yw09bIfrzPlUSLaJMI0b162sO2VqP3pRuhydGlUQrK/YtXcpECq aR2S3oNGPppyeuyW+9MPISmp5y6xRv+4lgLX4wGd8GUWlMkJ08gyhkz4EKP8bYuTh1xkNQFRBlL 4uIWJ X-Gm-Gg: ASbGncvUPr5730uLZ/t/La14Km5SYhZXuj43Iwo6XfSf9z0/vzFHtFv/UCdW+CEUaT/ HYBkpuR7DlHH6cPJGzypZ/mXdkMsHZCTlj8Q5eiUy4Hv7Luwq0L+EXG8103NHtVKsSdXkWoQoT8 zca/MeT8KOm6/2MO/1f6gj2BIXTwCFQ63FMCngFMifwHl4SjXVclE8d1fJAZXCv0VN70Hmb4sRH WGr6eBIZENHCAEkqf5YlpILzHVK2LoNIYbR9g== X-Google-Smtp-Source: AGHT+IG9U1RkmAjCsaZkbHJvJ5nu4yp+BcYJp90LiOTeDBKduQ1hWfRCwdTnNEzAhSGitcQ4jLpnsQ== X-Received: by 2002:a05:600c:138c:b0:434:9d76:5031 with SMTP id 5b1f17b1804b1-434d52a1a87mr1200475e9.1.1733329620387; Wed, 04 Dec 2024 08:27:00 -0800 (PST) Received: from localhost ([2a00:79e0:9d:4:4606:5fa1:8ade:6950]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-385dd99504csm16808066f8f.85.2024.12.04.08.26.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Dec 2024 08:26:59 -0800 (PST) From: Jann Horn Date: Wed, 04 Dec 2024 17:26:19 +0100 Subject: [PATCH v2 1/3] udmabuf: fix racy memfd sealing check Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241204-udmabuf-fixes-v2-1-23887289de1c@google.com> References: <20241204-udmabuf-fixes-v2-0-23887289de1c@google.com> In-Reply-To: <20241204-udmabuf-fixes-v2-0-23887289de1c@google.com> To: Gerd Hoffmann , Vivek Kasireddy , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= , Simona Vetter , John Stultz , Andrew Morton , "Joel Fernandes (Google)" Cc: dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, Jann Horn , Julian Orth , stable@vger.kernel.org X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=ed25519-sha256; t=1733329589; l=1788; i=jannh@google.com; s=20240730; h=from:subject:message-id; bh=Tb4zTg8gwUbDaogCnGrqjqwGKOpD1jahUvTB+lbqtzQ=; b=x0rM9Iqs4R9cqZm4OwMo3VWit21K6SeS2leyIeQreRfqXoZoMTJdgc0TRz3BeylxDekXItOM6 v3yPm+oXfdYAGerYEcgb+A8uMYKhMtEJ8Hr0uOzDDVLWGCHtKOz9Wou X-Developer-Key: i=jannh@google.com; a=ed25519; pk=AljNtGOzXeF6khBXDJVVvwSEkVDGnnZZYqfWhP1V+C8= The current check_memfd_seals() is racy: Since we first do check_memfd_seals() and then udmabuf_pin_folios() without holding any relevant lock across both, F_SEAL_WRITE can be set in between. This is problematic because we can end up holding pins to pages in a write-sealed memfd. Fix it using the inode lock, that's probably the easiest way. In the future, we might want to consider moving this logic into memfd, especially if anyone else wants to use memfd_pin_folios(). Reported-by: Julian Orth Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219106 Closes: https://lore.kernel.org/r/CAG48ez0w8HrFEZtJkfmkVKFDhE5aP7nz=obrimeTgpD+StkV9w@mail.gmail.com Fixes: fbb0de795078 ("Add udmabuf misc device") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn Acked-by: Joel Fernandes (Google) Acked-by: Vivek Kasireddy --- drivers/dma-buf/udmabuf.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 8ce1f074c2d32a0a9f59ff7184359e37d56548c6..c1d8c2766d6d36fc5fe1b3d73057f6e01ec6678f 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -436,14 +436,19 @@ static long udmabuf_create(struct miscdevice *device, goto err; } + /* + * Take the inode lock to protect against concurrent + * memfd_add_seals(), which takes this lock in write mode. + */ + inode_lock_shared(file_inode(memfd)); ret = check_memfd_seals(memfd); - if (ret < 0) { - fput(memfd); - goto err; - } + if (ret) + goto out_unlock; ret = udmabuf_pin_folios(ubuf, memfd, list[i].offset, list[i].size, folios); +out_unlock: + inode_unlock_shared(file_inode(memfd)); fput(memfd); if (ret) goto err; From patchwork Wed Dec 4 16:26:20 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jann Horn X-Patchwork-Id: 13894070 Received: from mail-wm1-f53.google.com (mail-wm1-f53.google.com [209.85.128.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9575A20C499 for ; Wed, 4 Dec 2024 16:27:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.53 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733329625; cv=none; b=fIqPv3cGSRZ3L+ZoRZV91A1No9eQphpPGMumam3VRtD1X66nTS6TxhSd0cebh9NMIEHZ5taA+zEeJ7cxf34aHmDquvil/imVAx35lodQNFGRA6Fq7wvjxhaLpYHTqFhzYxT6RYkjQeRbfGm7LEKckoHpzxOBp8LfiKxL7rU7W6A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733329625; c=relaxed/simple; bh=fJkw2rLMTtXSXhulM8gnhffaFfLiI1f0yAZSjHGcIX0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=uIA5dd7/vIM5aAtIybCYwIcemSmY42BrwJ+Am1YJPI2n1YGjN2R9czbcg02m4yB30fGd/uPlO4V3cUnT46r8H69fQ7t9pgKrNdzYLer1gRi/um+J2QVweeqLcridPrZd4IBxGfe2gcIvmbCd0+Ai4M3QVxiuEnRRpmLITahr+yQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=4n1WkQHH; arc=none smtp.client-ip=209.85.128.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="4n1WkQHH" Received: by mail-wm1-f53.google.com with SMTP id 5b1f17b1804b1-4349ea54db7so61765e9.0 for ; Wed, 04 Dec 2024 08:27:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1733329622; x=1733934422; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=ndPjCiEchgmhN558RiQyP0Yt1FLq3iHOnb50r5toGHE=; b=4n1WkQHHwDnRHDoSIIEdJN67nUStmUBcHEIdSHqvKaDm5qIzzeOEW+FB99ksnz+Y4B sB55fX7bW42s94SZXDFZy+jX5zRFdq396No43GpqTPT2w9LMFeMMXS1UCT3UWWlRokUW jMHlxpY55+RCl98zk/WkZY8RF1bJgLFi5W3mn+pU8SCM2ugOa01Gj2yGiWsr9IV8C4CH gBaQzIYQwRUib4RlMxXX7lQkv/P+6LHHQBxt2UUzD6CNVSIchE01Sjg+HTuQH36mNaXK Jmke3uWfIOStAuD8Fk5cfMbH4RH/X8p4dVHTs9midILE1TrB2DpLsA9HPhOlsBmFt4ll ZlVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733329622; x=1733934422; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ndPjCiEchgmhN558RiQyP0Yt1FLq3iHOnb50r5toGHE=; b=U3F5AnfAuZcTb0wVxP9h22D84ZuQcLlr0q/qqfFtHIkT5AS7i+GV0WEktQom8HRVTS VaRYNXXEtuUt0UpM2iTZKoGBXkSI0xI9hxeXOr9ghW+5AJCoa87Wz+yxSnDIiHiVU7a7 zd2Ha2tcNt97ssDZs2U4l9zTVq8Lp1W/kMFwUjv+04vDh9YmCG78MPRmNSBl5LOReJKz x+fQtjoFXZboubwrtokDhqu/2J2igK6OC3pcRPw5+3UTpA3ZatNlWp2rPOb44II80SkB 6SyOG50CpnlhnTAZnxHHHTwsb3VRA+ebO+CJceLNpr7sFRSkXiujsd53jOmH81D6ljlY r9Lw== X-Forwarded-Encrypted: i=1; AJvYcCUfzdODKCalA7X7juy2Vfdh5w7P/YBlsi8FoFau9HBqDLerLtL+I0wvjPmaZ2CCjnVFGhn0tIlzz/9iqQ==@vger.kernel.org X-Gm-Message-State: AOJu0Yy1La7Kpky/1Wn6HM91PeuKORZBAURVgZPXo4AMY1nmu4n1fEHA vudjJhRRWoM6a7Dqh+4LiJA/j2cFJ2KpDTtDwBDvyUC8CwCEP4GxHI3OFL9T9Q== X-Gm-Gg: ASbGnctvNUI03WsmdHh2pynuVqZRRKpYRo4td3u1EY6n7jkRAgJacbed87osilCX6YA UjICSNxrM+hpX8Psr5Z9mMvbHDlumcrcDHHvC2sJOyebbvPQuSp1MDteGlh9mT9L56pSmBc4rfp e07OhAIBqKPoMLdK4jvqm0yOuzpprEMAaNabMEz9fbxdfKtIh81Xxnb5OHCmk7Da2jo1bsbEpu1 84fSPiJza+E1dzEGSeOzh9x4YUJJFTu3IgDdw== X-Google-Smtp-Source: AGHT+IHRNnKQuL0FzYJ9sRykYWh8jH2cm3zF2nEbZZRSS5rqUEb9oxCGR02zINfXQfHQRF/jLblOew== X-Received: by 2002:a05:600c:3ac8:b0:42c:9e35:cde6 with SMTP id 5b1f17b1804b1-434d4a5d4a4mr1384465e9.2.1733329621419; Wed, 04 Dec 2024 08:27:01 -0800 (PST) Received: from localhost ([2a00:79e0:9d:4:4606:5fa1:8ade:6950]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-385dec66e0esm16298133f8f.43.2024.12.04.08.27.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Dec 2024 08:27:00 -0800 (PST) From: Jann Horn Date: Wed, 04 Dec 2024 17:26:20 +0100 Subject: [PATCH v2 2/3] udmabuf: also check for F_SEAL_FUTURE_WRITE Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241204-udmabuf-fixes-v2-2-23887289de1c@google.com> References: <20241204-udmabuf-fixes-v2-0-23887289de1c@google.com> In-Reply-To: <20241204-udmabuf-fixes-v2-0-23887289de1c@google.com> To: Gerd Hoffmann , Vivek Kasireddy , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= , Simona Vetter , John Stultz , Andrew Morton , "Joel Fernandes (Google)" Cc: dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, Jann Horn , stable@vger.kernel.org X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=ed25519-sha256; t=1733329589; l=1031; i=jannh@google.com; s=20240730; h=from:subject:message-id; bh=fJkw2rLMTtXSXhulM8gnhffaFfLiI1f0yAZSjHGcIX0=; b=NhY0leWwseGXjAz22badChvpbfQCiGr6eextWw4sxPskRjjjSOJH/wPzPkPy4s/BHbCWwcM7p LC618vgQbjWCzsNvNI9+Z53VJP06p8zJnx97CEnj6l4JcYpay7agU4B X-Developer-Key: i=jannh@google.com; a=ed25519; pk=AljNtGOzXeF6khBXDJVVvwSEkVDGnnZZYqfWhP1V+C8= When F_SEAL_FUTURE_WRITE was introduced, it was overlooked that udmabuf must reject memfds with this flag, just like ones with F_SEAL_WRITE. Fix it by adding F_SEAL_FUTURE_WRITE to SEALS_DENIED. Fixes: ab3948f58ff8 ("mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfd") Cc: stable@vger.kernel.org Acked-by: Vivek Kasireddy Signed-off-by: Jann Horn Reviewed-by: Joel Fernandes (Google) --- drivers/dma-buf/udmabuf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index c1d8c2766d6d36fc5fe1b3d73057f6e01ec6678f..b330b99fcc7619a05bb7dc2aeeb9c82faf9a387b 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -297,7 +297,7 @@ static const struct dma_buf_ops udmabuf_ops = { }; #define SEALS_WANTED (F_SEAL_SHRINK) -#define SEALS_DENIED (F_SEAL_WRITE) +#define SEALS_DENIED (F_SEAL_WRITE|F_SEAL_FUTURE_WRITE) static int check_memfd_seals(struct file *memfd) { From patchwork Wed Dec 4 16:26:21 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jann Horn X-Patchwork-Id: 13894072 Received: from mail-wm1-f42.google.com (mail-wm1-f42.google.com [209.85.128.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 024FF20CCE4 for ; Wed, 4 Dec 2024 16:27:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.42 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733329626; cv=none; b=Quz1h6+VAhHXeqrmys0WU8cHts5zXv7uVSu176StX8n9Bm5nNpcRHaG3TdwG3u6wyaHv+g8mhVGVZFCWaHYu7MQ61qLRND6GMe6G05dIVQSZWczIo2foIQKlTFtkFiZV5KIrx/Un5KWszVoT6oTQg1s7npFDZ48LmrpX49ej8gQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733329626; c=relaxed/simple; bh=mvwHL7Jb84Pbju4MjxbJaCZAU90KwtuuZ/LtjIuw+f8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=jbhBBrD6osI+ZjjZpRSVVdaYHYsQ6eo3EoHPVIdzzBSn6tmRwWfoT53hqVKxfsjdLV625XOtkDlO+8eRIMlOvctHgEWhXLdHO1dVBVSFdMhn7+iOZAjK2Mmb2GKHrzTOU1AMNFxbGDi3clRUQLWejByuHy/NONdf5ZuM3hJDvyA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=0tm4hcD9; arc=none smtp.client-ip=209.85.128.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="0tm4hcD9" Received: by mail-wm1-f42.google.com with SMTP id 5b1f17b1804b1-4349ea54db7so61795e9.0 for ; Wed, 04 Dec 2024 08:27:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1733329623; x=1733934423; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=4W1li+PQJAySFeW+G0OUEYywmlbqWEh+T217K5HBe5s=; b=0tm4hcD9Rdc1/uJ8eW9oZMKN8dUnmpthZPz4oE9NOkhfLo0TzCWMOv274JrGRuBG1j sKm15naXCQbSAC7aL0yIk4Yzzi0NzbG128GZRHN+iPDFNlwMjdKchb4xK06oSTD44Moy Xu/j+wjhg/dIC+OurYLoiguJuC/fq9qj1fFa2x7Me4sRP7+TqDF4dXQnYb1fS9N45TjN xgkWuMARc0OAiKfrEpypVgOWgBVOSeV/Z47LqhKYlMKrI7xuj9u2tyaVdtfsGacryZne 84hsPe+IfbpJwEOpaPhmI1qTHu64gAsMxbhbWFGOxEqcUv0pXnXrQg9tUunHVnvoSaQB 8XlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733329623; x=1733934423; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=4W1li+PQJAySFeW+G0OUEYywmlbqWEh+T217K5HBe5s=; b=PEkNJ7gFWf+wAQ4FQBw0/PO6mspktecHZ1MpUy8URWdZRKrN74s0OMhAnGkbzeVoav 8O0x9rNmiOGx4Gyg8XUK2gldYjZrfT4B7vd2Kd23RD/EytzBJWeLeibf7LFbQoUOFcaC mbO+Ej3bQ9ozsVIjTJMV4++78qmr1WXzxqSQI6Aim5us87EH4W8F8LYCheYuA3/KPBxm vzzN610Uzb+lyVD20G5Is5v+zgrU748NwnNk6GaHTtGiEw5Vq9GsNuY/btZFWkHbYOs4 sYHYY3gwDje85MfSTMQhEWpvvu2LH+KQLBTf9A2RVjCtRERM4kUSsn+1WZVJL0+e/IY/ Q4hQ== X-Forwarded-Encrypted: i=1; AJvYcCX24xQMGQHVNNlSd1xJYd2F49D6XGXE9OaYKffLO1qeup246+n20SvOz4g576LNDBgBrA98aZHQEsGxKQ==@vger.kernel.org X-Gm-Message-State: AOJu0Yw+k+2dl/UlazlykRqbRociwi0qkyVY/NRCppXQkUHByRlzacSg AUSwRRTh0m/FnWimB6OcliaL9OQaE2hf+6zo/85wLBXSPF5qpcTBx73lvQblmw== X-Gm-Gg: ASbGncskvUNFnsfsnJeX4U/ZJZbCLlsXXMD0J+Y7lXVSrkkizMDi7HYjrMPO9EOvMKz tWJnwN9O75FfLy5o8GSBrAaou3B1qDcFbcMKTK3cyg4445HcBc0Z4o7Uyc0B2JnohrCk8qMAl5p l7M8vfY7O5S6FyveVgiEksW2VbQrp1PpefIqQ6SD+y3Hpye5zceZ0OvvBkHjYJXFpp7z/Tdn3dM BY02fS+vXtHVo4MXybMgbikx1PZQpX6UCi30G4= X-Google-Smtp-Source: AGHT+IFxTlGmGXtO+gti6IDe6nN/9i5MoY6EIkDL/S+U10Uwbut4N21TN5+9JMZjadgnuQEdINJ5lg== X-Received: by 2002:a05:600c:138c:b0:434:9d76:5031 with SMTP id 5b1f17b1804b1-434d52a1a87mr1200535e9.1.1733329622396; Wed, 04 Dec 2024 08:27:02 -0800 (PST) Received: from localhost ([2a00:79e0:9d:4:4606:5fa1:8ade:6950]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-385e391656csm13529589f8f.47.2024.12.04.08.27.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Dec 2024 08:27:01 -0800 (PST) From: Jann Horn Date: Wed, 04 Dec 2024 17:26:21 +0100 Subject: [PATCH v2 3/3] udmabuf: fix memory leak on last export_udmabuf() error path Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241204-udmabuf-fixes-v2-3-23887289de1c@google.com> References: <20241204-udmabuf-fixes-v2-0-23887289de1c@google.com> In-Reply-To: <20241204-udmabuf-fixes-v2-0-23887289de1c@google.com> To: Gerd Hoffmann , Vivek Kasireddy , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= , Simona Vetter , John Stultz , Andrew Morton , "Joel Fernandes (Google)" Cc: dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, Jann Horn X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=ed25519-sha256; t=1733329589; l=2920; i=jannh@google.com; s=20240730; h=from:subject:message-id; bh=mvwHL7Jb84Pbju4MjxbJaCZAU90KwtuuZ/LtjIuw+f8=; b=fcP3sbdyj//3/2F+j7CV5MfjiClV4Op+98VqArx+dvhb/6GkinHSzqeg9LJqzsq7iAU0UxgUh QpLwT4usxp1DhuRdSWGAKD7NSw4TKBtLSJfIgmMudebJ46OZuQdrIzb X-Developer-Key: i=jannh@google.com; a=ed25519; pk=AljNtGOzXeF6khBXDJVVvwSEkVDGnnZZYqfWhP1V+C8= In export_udmabuf(), if dma_buf_fd() fails because the FD table is full, a dma_buf owning the udmabuf has already been created; but the error handling in udmabuf_create() will tear down the udmabuf without doing anything about the containing dma_buf. This leaves a dma_buf in memory that contains a dangling pointer; though that doesn't seem to lead to anything bad except a memory leak. Fix it by moving the dma_buf_fd() call out of export_udmabuf() so that we can give it different error handling. Note that the shape of this code changed a lot in commit 5e72b2b41a21 ("udmabuf: convert udmabuf driver to use folios"); but the memory leak seems to have existed since the introduction of udmabuf. Fixes: fbb0de795078 ("Add udmabuf misc device") Acked-by: Vivek Kasireddy Signed-off-by: Jann Horn --- drivers/dma-buf/udmabuf.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index b330b99fcc7619a05bb7dc2aeeb9c82faf9a387b..cc7398cc17d67fca0634e763534901f8e6b454f8 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -317,12 +317,10 @@ static int check_memfd_seals(struct file *memfd) return 0; } -static int export_udmabuf(struct udmabuf *ubuf, - struct miscdevice *device, - u32 flags) +static struct dma_buf *export_udmabuf(struct udmabuf *ubuf, + struct miscdevice *device) { DEFINE_DMA_BUF_EXPORT_INFO(exp_info); - struct dma_buf *buf; ubuf->device = device; exp_info.ops = &udmabuf_ops; @@ -330,11 +328,7 @@ static int export_udmabuf(struct udmabuf *ubuf, exp_info.priv = ubuf; exp_info.flags = O_RDWR; - buf = dma_buf_export(&exp_info); - if (IS_ERR(buf)) - return PTR_ERR(buf); - - return dma_buf_fd(buf, flags); + return dma_buf_export(&exp_info); } static long udmabuf_pin_folios(struct udmabuf *ubuf, struct file *memfd, @@ -391,6 +385,7 @@ static long udmabuf_create(struct miscdevice *device, struct folio **folios = NULL; pgoff_t pgcnt = 0, pglimit; struct udmabuf *ubuf; + struct dma_buf *dmabuf; long ret = -EINVAL; u32 i, flags; @@ -455,9 +450,20 @@ static long udmabuf_create(struct miscdevice *device, } flags = head->flags & UDMABUF_FLAGS_CLOEXEC ? O_CLOEXEC : 0; - ret = export_udmabuf(ubuf, device, flags); - if (ret < 0) + dmabuf = export_udmabuf(ubuf, device); + if (IS_ERR(dmabuf)) { + ret = PTR_ERR(dmabuf); goto err; + } + /* + * Ownership of ubuf is held by the dmabuf from here. + * If the following dma_buf_fd() fails, dma_buf_put() cleans up both the + * dmabuf and the ubuf (through udmabuf_ops.release). + */ + + ret = dma_buf_fd(dmabuf, flags); + if (ret < 0) + dma_buf_put(dmabuf); kvfree(folios); return ret;