CVE-2023-53752

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net: deal with integer overflows in kmalloc_reserve()<br /> <br /> Blamed commit changed:<br /> ptr = kmalloc(size);<br /> if (ptr)<br /> size = ksize(ptr);<br /> <br /> size = kmalloc_size_roundup(size);<br /> ptr = kmalloc(size);<br /> <br /> This allowed various crash as reported by syzbot [1]<br /> and Kyle Zeng.<br /> <br /> Problem is that if @size is bigger than 0x80000001,<br /> kmalloc_size_roundup(size) returns 2^32.<br /> <br /> kmalloc_reserve() uses a 32bit variable (obj_size),<br /> so 2^32 is truncated to 0.<br /> <br /> kmalloc(0) returns ZERO_SIZE_PTR which is not handled by<br /> skb allocations.<br /> <br /> Following trace can be triggered if a netdev-&gt;mtu is set<br /> close to 0x7fffffff<br /> <br /> We might in the future limit netdev-&gt;mtu to more sensible<br /> limit (like KMALLOC_MAX_SIZE).<br /> <br /> This patch is based on a syzbot report, and also a report<br /> and tentative fix from Kyle Zeng.<br /> <br /> [1]<br /> BUG: KASAN: user-memory-access in __build_skb_around net/core/skbuff.c:294 [inline]<br /> BUG: KASAN: user-memory-access in __alloc_skb+0x3c4/0x6e8 net/core/skbuff.c:527<br /> Write of size 32 at addr 00000000fffffd10 by task syz-executor.4/22554<br /> <br /> CPU: 1 PID: 22554 Comm: syz-executor.4 Not tainted 6.1.39-syzkaller #0<br /> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023<br /> Call trace:<br /> dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:279<br /> show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:286<br /> __dump_stack lib/dump_stack.c:88 [inline]<br /> dump_stack_lvl+0x120/0x1a0 lib/dump_stack.c:106<br /> print_report+0xe4/0x4b4 mm/kasan/report.c:398<br /> kasan_report+0x150/0x1ac mm/kasan/report.c:495<br /> kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:189<br /> memset+0x40/0x70 mm/kasan/shadow.c:44<br /> __build_skb_around net/core/skbuff.c:294 [inline]<br /> __alloc_skb+0x3c4/0x6e8 net/core/skbuff.c:527<br /> alloc_skb include/linux/skbuff.h:1316 [inline]<br /> igmpv3_newpack+0x104/0x1088 net/ipv4/igmp.c:359<br /> add_grec+0x81c/0x1124 net/ipv4/igmp.c:534<br /> igmpv3_send_cr net/ipv4/igmp.c:667 [inline]<br /> igmp_ifc_timer_expire+0x1b0/0x1008 net/ipv4/igmp.c:810<br /> call_timer_fn+0x1c0/0x9f0 kernel/time/timer.c:1474<br /> expire_timers kernel/time/timer.c:1519 [inline]<br /> __run_timers+0x54c/0x710 kernel/time/timer.c:1790<br /> run_timer_softirq+0x28/0x4c kernel/time/timer.c:1803<br /> _stext+0x380/0xfbc<br /> ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:79<br /> call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:891<br /> do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:84<br /> invoke_softirq kernel/softirq.c:437 [inline]<br /> __irq_exit_rcu+0x1c0/0x4cc kernel/softirq.c:683<br /> irq_exit_rcu+0x14/0x78 kernel/softirq.c:695<br /> el0_interrupt+0x7c/0x2e0 arch/arm64/kernel/entry-common.c:717<br /> __el0_irq_handler_common+0x18/0x24 arch/arm64/kernel/entry-common.c:724<br /> el0t_64_irq_handler+0x10/0x1c arch/arm64/kernel/entry-common.c:729<br /> el0t_64_irq+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584