{"id":1839978,"url":"http://patchwork.ozlabs.org/api/patches/1839978/?format=json","web_url":"http://patchwork.ozlabs.org/project/ubuntu-kernel/patch/20230927004025.119111-6-cascardo@canonical.com/","project":{"id":15,"url":"http://patchwork.ozlabs.org/api/projects/15/?format=json","name":"Ubuntu Kernel","link_name":"ubuntu-kernel","list_id":"kernel-team.lists.ubuntu.com","list_email":"kernel-team@lists.ubuntu.com","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20230927004025.119111-6-cascardo@canonical.com>","list_archive_url":null,"date":"2023-09-27T00:40:25","name":"[SRU,OEM-6.1,Lunar,5/5] net: deal with integer overflows in kmalloc_reserve()","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"6fa0b6de0482aa079bcd521ec7fd130c6a1e4894","submitter":{"id":70574,"url":"http://patchwork.ozlabs.org/api/people/70574/?format=json","name":"Thadeu Lima de Souza Cascardo","email":"cascardo@canonical.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/ubuntu-kernel/patch/20230927004025.119111-6-cascardo@canonical.com/mbox/","series":[{"id":375017,"url":"http://patchwork.ozlabs.org/api/series/375017/?format=json","web_url":"http://patchwork.ozlabs.org/project/ubuntu-kernel/list/?series=375017","date":"2023-09-27T00:40:20","name":"CVE-2023-42752","version":1,"mbox":"http://patchwork.ozlabs.org/series/375017/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/1839978/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/1839978/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":"legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ubuntu.com\n (client-ip=185.125.189.65; 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Wed, 27 Sep 2023 00:40:44 +0000 (UTC)"],"From":"Thadeu Lima de Souza Cascardo ","To":"kernel-team@lists.ubuntu.com","Subject":"[SRU OEM-6.1,\n Lunar 5/5] net: deal with integer overflows in kmalloc_reserve()","Date":"Tue, 26 Sep 2023 21:40:25 -0300","Message-Id":"<20230927004025.119111-6-cascardo@canonical.com>","X-Mailer":"git-send-email 2.34.1","In-Reply-To":"<20230927004025.119111-1-cascardo@canonical.com>","References":"<20230927004025.119111-1-cascardo@canonical.com>","MIME-Version":"1.0","X-BeenThere":"kernel-team@lists.ubuntu.com","X-Mailman-Version":"2.1.20","Precedence":"list","List-Id":"Kernel team discussions ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Content-Type":"text/plain; charset=\"utf-8\"","Content-Transfer-Encoding":"base64","Errors-To":"kernel-team-bounces@lists.ubuntu.com","Sender":"\"kernel-team\" "},"content":"From: Eric Dumazet \n\ncommit 915d975b2ffa58a14bfcf16fafe00c41315949ff upstream.\n\nBlamed commit changed:\n ptr = kmalloc(size);\n if (ptr)\n size = ksize(ptr);\n\nto:\n size = kmalloc_size_roundup(size);\n ptr = kmalloc(size);\n\nThis allowed various crash as reported by syzbot [1]\nand Kyle Zeng.\n\nProblem is that if @size is bigger than 0x80000001,\nkmalloc_size_roundup(size) returns 2^32.\n\nkmalloc_reserve() uses a 32bit variable (obj_size),\nso 2^32 is truncated to 0.\n\nkmalloc(0) returns ZERO_SIZE_PTR which is not handled by\nskb allocations.\n\nFollowing trace can be triggered if a netdev->mtu is set\nclose to 0x7fffffff\n\nWe might in the future limit netdev->mtu to more sensible\nlimit (like KMALLOC_MAX_SIZE).\n\nThis patch is based on a syzbot report, and also a report\nand tentative fix from Kyle Zeng.\n\n[1]\nBUG: KASAN: user-memory-access in __build_skb_around net/core/skbuff.c:294 [inline]\nBUG: KASAN: user-memory-access in __alloc_skb+0x3c4/0x6e8 net/core/skbuff.c:527\nWrite of size 32 at addr 00000000fffffd10 by task syz-executor.4/22554\n\nCPU: 1 PID: 22554 Comm: syz-executor.4 Not tainted 6.1.39-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023\nCall trace:\ndump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:279\nshow_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:286\n__dump_stack lib/dump_stack.c:88 [inline]\ndump_stack_lvl+0x120/0x1a0 lib/dump_stack.c:106\nprint_report+0xe4/0x4b4 mm/kasan/report.c:398\nkasan_report+0x150/0x1ac mm/kasan/report.c:495\nkasan_check_range+0x264/0x2a4 mm/kasan/generic.c:189\nmemset+0x40/0x70 mm/kasan/shadow.c:44\n__build_skb_around net/core/skbuff.c:294 [inline]\n__alloc_skb+0x3c4/0x6e8 net/core/skbuff.c:527\nalloc_skb include/linux/skbuff.h:1316 [inline]\nigmpv3_newpack+0x104/0x1088 net/ipv4/igmp.c:359\nadd_grec+0x81c/0x1124 net/ipv4/igmp.c:534\nigmpv3_send_cr net/ipv4/igmp.c:667 [inline]\nigmp_ifc_timer_expire+0x1b0/0x1008 net/ipv4/igmp.c:810\ncall_timer_fn+0x1c0/0x9f0 kernel/time/timer.c:1474\nexpire_timers kernel/time/timer.c:1519 [inline]\n__run_timers+0x54c/0x710 kernel/time/timer.c:1790\nrun_timer_softirq+0x28/0x4c kernel/time/timer.c:1803\n_stext+0x380/0xfbc\n____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:79\ncall_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:891\ndo_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:84\ninvoke_softirq kernel/softirq.c:437 [inline]\n__irq_exit_rcu+0x1c0/0x4cc kernel/softirq.c:683\nirq_exit_rcu+0x14/0x78 kernel/softirq.c:695\nel0_interrupt+0x7c/0x2e0 arch/arm64/kernel/entry-common.c:717\n__el0_irq_handler_common+0x18/0x24 arch/arm64/kernel/entry-common.c:724\nel0t_64_irq_handler+0x10/0x1c arch/arm64/kernel/entry-common.c:729\nel0t_64_irq+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584\n\nFixes: 12d6c1d3a2ad (\"skbuff: Proactively round up to kmalloc bucket size\")\nReported-by: syzbot \nReported-by: Kyle Zeng \nSigned-off-by: Eric Dumazet \nCc: Kees Cook \nCc: Vlastimil Babka \nSigned-off-by: David S. Miller \n[Ajay: Regenerated the patch for v6.1.y]\nSigned-off-by: Ajay Kaher \nSigned-off-by: Greg Kroah-Hartman \n(cherry picked from commit 31cf7853a940181593e4472fc56f46574123f9f6 linux-6.1.y)\nCVE-2023-42752\nSigned-off-by: Thadeu Lima de Souza Cascardo \n---\n net/core/skbuff.c | 10 ++++++++--\n 1 file changed, 8 insertions(+), 2 deletions(-)","diff":"diff --git a/net/core/skbuff.c b/net/core/skbuff.c\nindex 7219fb97a560..19441a892c9b 100644\n--- a/net/core/skbuff.c\n+++ b/net/core/skbuff.c\n@@ -483,11 +483,17 @@ static void *kmalloc_reserve(unsigned int *size, gfp_t flags, int node,\n \t\t\t bool *pfmemalloc)\n {\n \tbool ret_pfmemalloc = false;\n-\tunsigned int obj_size;\n+\tsize_t obj_size;\n \tvoid *obj;\n \n \tobj_size = SKB_HEAD_ALIGN(*size);\n-\t*size = obj_size = kmalloc_size_roundup(obj_size);\n+\n+\tobj_size = kmalloc_size_roundup(obj_size);\n+\t/* The following cast might truncate high-order bits of obj_size, this\n+\t * is harmless because kmalloc(obj_size >= 2^32) will fail anyway.\n+\t */\n+\t*size = (unsigned int)obj_size;\n+\n \t/*\n \t * Try a regular allocation, when that fails and we're not entitled\n \t * to the reserves, fail.\n","prefixes":["SRU","OEM-6.1","Lunar","5/5"]}