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uprobes: fix kernel info leak via "[uprobes]" vma

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xol_add_vma() maps the uninitialized page allocated by __create_xol_area()
into userspace. On some architectures (x86) this memory is readable even
without VM_READ, VM_EXEC results in the same pgprot_t as VM_EXEC|VM_READ,
although this doesn't really matter, debugger can read this memory anyway.

Link: https://lore.kernel.org/all/20240929162047.GA12611@redhat.com/

Reported-by: Will Deacon <will@kernel.org>
Fixes: d4b3b6384f ("uprobes/core: Allocate XOL slots for uprobes use")
Cc: stable@vger.kernel.org
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
This commit is contained in:
Oleg Nesterov 2024-09-29 18:20:47 +02:00 committed by Masami Hiramatsu (Google)
parent ad46e8f95e
commit 34820304cc
1 changed files with 1 additions and 1 deletions
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2
kernel/events/uprobes.c
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@ -1545,7 +1545,7 @@ static struct xol_area *__create_xol_area(unsigned long vaddr)
if (!area->bitmap)
goto free_area;
area->page = alloc_page(GFP_HIGHUSER);
area->page = alloc_page(GFP_HIGHUSER | __GFP_ZERO);
if (!area->page)
goto free_bitmap;