FAILED: patch "[PATCH] uprobes: fix kernel info leak via "[uprobes]" vma" failed to apply to 4.19-stable tree

FAILED: patch "[PATCH] uprobes: fix kernel info leak via "[uprobes]" vma" failed to apply to 4.19-stable tree

[gregkh]

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x 34820304cc2cd1804ee1f8f3504ec77813d29c8e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024100702-doze-flashy-bbe9@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

34820304cc2c ("uprobes: fix kernel info leak via "[uprobes]" vma")
2abbcc099ec6 ("uprobes: turn xol_area->pages[2] into xol_area->page")
6d27a31ef195 ("uprobes: introduce the global struct vm_special_mapping xol_mapping")
ff474a78cef5 ("uprobe: Add uretprobe syscall to speed up return probe")
1713b63a07a2 ("x86/shstk: Make return uprobe work with shadow stack")
05e36022c054 ("x86/shstk: Handle signals for shadow stack")
928054769dbd ("x86/shstk: Introduce routines modifying shstk")
b2926a36b97a ("x86/shstk: Handle thread shadow stack")
2d39a6add422 ("x86/shstk: Add user-mode shadow stack support")
98cfa4630912 ("x86: Introduce userspace API for shadow stack")
2da5b91fe409 ("x86/traps: Move control protection handler to separate file")
2f8794bd087e ("x86/mm: Provide arch_prctl() interface for LAM")
74c228d20a51 ("x86/uaccess: Provide untagged_addr() and remove tags before address check")
82721d8b25d7 ("x86/mm: Handle LAM on context switch")
5ef495e55f07 ("x86: Allow atomic MM_CONTEXT flags setting")
94a855111ed9 ("Merge tag 'x86_core_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 34820304cc2cd1804ee1f8f3504ec77813d29c8e Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Sun, 29 Sep 2024 18:20:47 +0200
Subject: [PATCH] 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: Will Deacon <will@kernel.org>
Fixes: d4b3b6384f98 ("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>

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 2ec796e2f055..4b52cb2ae6d6 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -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;