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;