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charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam12 X-Rspam-User: X-Rspamd-Queue-Id: 99D6140010 X-Stat-Signature: cxg5bwdqeq1n8k35ffxpk6q75dfbc6x4 X-HE-Tag: 1764946787-587589 X-HE-Meta: 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 AzL7wiId 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Jiayuan Chen Syzkaller reported a memory out-of-bounds bug [1]. This patch fixes two issues: 1. In vrealloc the KASAN_VMALLOC_VM_ALLOC flag is missing when unpoisoning the extended region. This flag is required to correctly associate the allocation with KASAN's vmalloc tracking. Note: In contrast, vzalloc (via __vmalloc_node_range_noprof) explicitly sets KASAN_VMALLOC_VM_ALLOC and calls kasan_unpoison_vmalloc() with it. vrealloc must behave consistently =E2=80=94 especially when reusing exis= ting vmalloc regions =E2=80=94 to ensure KASAN can track allocations correctl= y. 2. When vrealloc reuses an existing vmalloc region (without allocating new pages) KASAN generates a new tag, which breaks tag-based memory access tracking. Introduce KASAN_VMALLOC_KEEP_TAG, a new KASAN flag that allows reusing the tag already attached to the pointer, ensuring consistent tag behavior during reallocation. Pass KASAN_VMALLOC_KEEP_TAG and KASAN_VMALLOC_VM_ALLOC to the kasan_unpoison_vmalloc inside vrealloc_node_align_noprof(). [1]: https://syzkaller.appspot.com/bug?extid=3D997752115a851cb0cf36 Fixes: a0309faf1cb0 ("mm: vmalloc: support more granular vrealloc() sizing"= ) Cc: Reported-by: syzbot+997752115a851cb0cf36@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68e243a2.050a0220.1696c6.007d.GAE@googl= e.com/T/ Signed-off-by: Jiayuan Chen Co-developed-by: Maciej Wieczor-Retman Signed-off-by: Maciej Wieczor-Retman Reviewed-by: Andrey Konovalov --- include/linux/kasan.h | 1 + mm/kasan/hw_tags.c | 2 +- mm/kasan/shadow.c | 4 +++- mm/vmalloc.c | 4 +++- 4 files changed, 8 insertions(+), 3 deletions(-) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index d12e1a5f5a9a..6d7972bb390c 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -28,6 +28,7 @@ typedef unsigned int __bitwise kasan_vmalloc_flags_t; #define KASAN_VMALLOC_INIT=09=09((__force kasan_vmalloc_flags_t)0x01u) #define KASAN_VMALLOC_VM_ALLOC=09=09((__force kasan_vmalloc_flags_t)0x02u) #define KASAN_VMALLOC_PROT_NORMAL=09((__force kasan_vmalloc_flags_t)0x04u) +#define KASAN_VMALLOC_KEEP_TAG=09=09((__force kasan_vmalloc_flags_t)0x08u) =20 #define KASAN_VMALLOC_PAGE_RANGE 0x1 /* Apply exsiting page range */ #define KASAN_VMALLOC_TLB_FLUSH 0x2 /* TLB flush */ diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index 1c373cc4b3fa..cbef5e450954 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -361,7 +361,7 @@ void *__kasan_unpoison_vmalloc(const void *start, unsig= ned long size, =09=09return (void *)start; =09} =20 -=09tag =3D kasan_random_tag(); +=09tag =3D (flags & KASAN_VMALLOC_KEEP_TAG) ? get_tag(start) : kasan_rando= m_tag(); =09start =3D set_tag(start, tag); =20 =09/* Unpoison and initialize memory up to size. */ diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c index 5d2a876035d6..5e47ae7fdd59 100644 --- a/mm/kasan/shadow.c +++ b/mm/kasan/shadow.c @@ -648,7 +648,9 @@ void *__kasan_unpoison_vmalloc(const void *start, unsig= ned long size, =09 !(flags & KASAN_VMALLOC_PROT_NORMAL)) =09=09return (void *)start; =20 -=09start =3D set_tag(start, kasan_random_tag()); +=09if (unlikely(!(flags & KASAN_VMALLOC_KEEP_TAG))) +=09=09start =3D set_tag(start, kasan_random_tag()); + =09kasan_unpoison(start, size, false); =09return (void *)start; } diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 798b2ed21e46..22a73a087135 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -4176,7 +4176,9 @@ void *vrealloc_node_align_noprof(const void *p, size_= t size, unsigned long align =09 */ =09if (size <=3D alloced_size) { =09=09kasan_unpoison_vmalloc(p + old_size, size - old_size, -=09=09=09=09 KASAN_VMALLOC_PROT_NORMAL); +=09=09=09=09 KASAN_VMALLOC_PROT_NORMAL | +=09=09=09=09 KASAN_VMALLOC_VM_ALLOC | +=09=09=09=09 KASAN_VMALLOC_KEEP_TAG); =09=09/* =09=09 * No need to zero memory here, as unused memory will have =09=09 * already been zeroed at initial allocation time or during --=20 2.52.0