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

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commit 34820304cc upstream.

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Oleg Nesterov
2024-10-07 19:46:01 +02:00
committed by Greg Kroah-Hartman
parent 9707c7895c
commit 21cb47db1e
1 changed files with 1 additions and 1 deletions
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kernel/events/uprobes.c
+1 -1
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@@ -1495,7 +1495,7 @@ static struct xol_area *__create_xol_area(unsigned long vaddr)
area->xol_mapping.name = "[uprobes]";
area->xol_mapping.pages = area->pages;
area->pages[0] = alloc_page(GFP_HIGHUSER);
area->pages[0] = alloc_page(GFP_HIGHUSER | __GFP_ZERO);
if (!area->pages[0])
goto free_bitmap;
area->pages[1] = NULL;