Commit 34820304 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Masami Hiramatsu (Google)
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uprobes: fix kernel info leak via "[uprobes]" vma 

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: default avatarWill Deacon <will@kernel.org>
Fixes: d4b3b638 ("uprobes/core: Allocate XOL slots for uprobes use")
Cc: stable@vger.kernel.org
Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
parent ad46e8f9

kernel/events/uprobes.c

+1 −1
Original line number Diff line number Diff line
@@ -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;