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| author | Oleg Nesterov <oleg@redhat.com> | 2024-09-11 15:13:20 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-09-17 01:07:01 -0700 |
| commit | ed8d5b0ce1d738e13c60d6b1a901a56d832e5070 (patch) | |
| tree | 1e94644a1af1b9af23b159bdd273c8101bee2482 /kernel | |
| parent | 242d12c98174584a18965cfab95778893872d650 (diff) | |
| download | lwn-ed8d5b0ce1d738e13c60d6b1a901a56d832e5070.tar.gz lwn-ed8d5b0ce1d738e13c60d6b1a901a56d832e5070.zip | |
Revert "uprobes: use vm_special_mapping close() functionality"
This reverts commit 08e28de1160a712724268fd33d77b32f1bc84d1c.
A malicious application can munmap() its "[uprobes]" vma and in this case
xol_mapping.close == uprobe_clear_state() will free the memory which can
be used by another thread, or the same thread when it hits the uprobe bp
afterwards.
Link: https://lkml.kernel.org/r/20240911131320.GA3448@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/uprobes.c | 36 | ||||
| -rw-r--r-- | kernel/fork.c | 1 |
2 files changed, 20 insertions, 17 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index c2d6b2d64de2..73cc47708679 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1482,22 +1482,6 @@ void * __weak arch_uprobe_trampoline(unsigned long *psize) return &insn; } -/* - * uprobe_clear_state - Free the area allocated for slots. - */ -static void uprobe_clear_state(const struct vm_special_mapping *sm, struct vm_area_struct *vma) -{ - struct xol_area *area = container_of(vma->vm_private_data, struct xol_area, xol_mapping); - - mutex_lock(&delayed_uprobe_lock); - delayed_uprobe_remove(NULL, vma->vm_mm); - mutex_unlock(&delayed_uprobe_lock); - - put_page(area->pages[0]); - kfree(area->bitmap); - kfree(area); -} - static struct xol_area *__create_xol_area(unsigned long vaddr) { struct mm_struct *mm = current->mm; @@ -1516,7 +1500,6 @@ static struct xol_area *__create_xol_area(unsigned long vaddr) area->xol_mapping.name = "[uprobes]"; area->xol_mapping.fault = NULL; - area->xol_mapping.close = uprobe_clear_state; area->xol_mapping.pages = area->pages; area->pages[0] = alloc_page(GFP_HIGHUSER); if (!area->pages[0]) @@ -1562,6 +1545,25 @@ static struct xol_area *get_xol_area(void) return area; } +/* + * uprobe_clear_state - Free the area allocated for slots. + */ +void uprobe_clear_state(struct mm_struct *mm) +{ + struct xol_area *area = mm->uprobes_state.xol_area; + + mutex_lock(&delayed_uprobe_lock); + delayed_uprobe_remove(NULL, mm); + mutex_unlock(&delayed_uprobe_lock); + + if (!area) + return; + + put_page(area->pages[0]); + kfree(area->bitmap); + kfree(area); +} + void uprobe_start_dup_mmap(void) { percpu_down_read(&dup_mmap_sem); diff --git a/kernel/fork.c b/kernel/fork.c index 61070248a7d3..3d590e51ce84 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1338,6 +1338,7 @@ static inline void __mmput(struct mm_struct *mm) { VM_BUG_ON(atomic_read(&mm->mm_users)); + uprobe_clear_state(mm); exit_aio(mm); ksm_exit(mm); khugepaged_exit(mm); /* must run before exit_mmap */ |