58 lines
2.3 KiB
Diff
58 lines
2.3 KiB
Diff
From a942817e22deae157ab3431184f3a760e616f696 Mon Sep 17 00:00:00 2001
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From: Rafael Aquini <raquini@redhat.com>
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Date: Wed, 1 Jul 2026 16:38:58 -0400
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Subject: [PATCH] procfs: fix possible double mmput() in do_procmap_query()
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JIRA: https://redhat.atlassian.net/browse/RHEL-189666
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CVE: CVE-2026-23199
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commit 61dc9f776705d6db6847c101b98fa4f0e9eb6fa3
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Author: Andrii Nakryiko <andrii@kernel.org>
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Date: Tue Feb 10 11:27:38 2026 -0800
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procfs: fix possible double mmput() in do_procmap_query()
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When user provides incorrectly sized buffer for build ID for PROCMAP_QUERY
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we return with -ENAMETOOLONG error. After recent changes this condition
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happens later, after we unlocked mmap_lock/per-VMA lock and did mmput(),
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so original goto out is now wrong and will double-mmput() mm_struct. Fix
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by jumping further to clean up only vm_file and name_buf.
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Link: https://lkml.kernel.org/r/20260210192738.3041609-1-andrii@kernel.org
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Fixes: b5cbacd7f86f ("procfs: avoid fetching build ID while holding VMA lock")
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Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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Reported-by: Ruikai Peng <ruikai@pwno.io>
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Reported-by: Thomas Gleixner <tglx@kernel.org>
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Tested-by: Thomas Gleixner <tglx@kernel.org>
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Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
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Reported-by: syzbot+237b5b985b78c1da9600@syzkaller.appspotmail.com
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Cc: Ruikai Peng <ruikai@pwno.io>
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Closes: https://lkml.kernel.org/r/CAFD3drOJANTZPuyiqMdqpiRwOKnHwv5QgMNZghCDr-WxdiHvMg@mail.gmail.com
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Closes: https://lore.kernel.org/all/698aaf3c.050a0220.3b3015.0088.GAE@google.com/T/#u
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Cc: <stable@vger.kernel.org>
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Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Signed-off-by: Rafael Aquini <raquini@redhat.com>
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diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
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index 27cc491..a574e8d 100644
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--- a/fs/proc/task_mmu.c
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+++ b/fs/proc/task_mmu.c
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@@ -581,7 +581,7 @@ static int do_procmap_query(struct proc_maps_private *priv, void __user *uarg)
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} else {
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if (karg.build_id_size < build_id_sz) {
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err = -ENAMETOOLONG;
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- goto out;
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+ goto out_file;
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}
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karg.build_id_size = build_id_sz;
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}
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@@ -609,6 +609,7 @@ static int do_procmap_query(struct proc_maps_private *priv, void __user *uarg)
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out:
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query_vma_teardown(mm, vma);
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mmput(mm);
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+out_file:
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if (vm_file)
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fput(vm_file);
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kfree(name_buf);
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