64 lines
2.2 KiB
Diff
64 lines
2.2 KiB
Diff
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Lidong Chen <lidong.chen@oracle.com>
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Date: Fri, 22 Nov 2024 06:27:59 +0000
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Subject: [PATCH] fs/jfs: Fix OOB read in jfs_getent()
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The JFS fuzzing revealed an OOB read in grub_jfs_getent(). The crash
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was caused by an invalid leaf nodes count, diro->dirpage->header.count,
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which was larger than the maximum number of leaf nodes allowed in an
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inode. This fix is to ensure that the leaf nodes count is validated in
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grub_jfs_opendir() before calling grub_jfs_getent().
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On the occasion replace existing raw numbers with newly defined constant.
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Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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Reviewed-by: Alec Brown <alec.r.brown@oracle.com>
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---
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grub-core/fs/jfs.c | 17 +++++++++++++++--
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1 file changed, 15 insertions(+), 2 deletions(-)
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diff --git a/grub-core/fs/jfs.c b/grub-core/fs/jfs.c
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index 6f7c43904..32dec7fb7 100644
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--- a/grub-core/fs/jfs.c
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+++ b/grub-core/fs/jfs.c
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@@ -41,6 +41,12 @@ GRUB_MOD_LICENSE ("GPLv3+");
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#define GRUB_JFS_TREE_LEAF 2
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+/*
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+ * Define max entries stored in-line in an inode.
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+ * https://jfs.sourceforge.net/project/pub/jfslayout.pdf
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+ */
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+#define GRUB_JFS_INODE_INLINE_ENTRIES 8
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+
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struct grub_jfs_sblock
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{
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/* The magic for JFS. It should contain the string "JFS1". */
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@@ -203,9 +209,9 @@ struct grub_jfs_inode
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grub_uint8_t freecnt;
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grub_uint8_t freelist;
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grub_uint32_t idotdot;
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- grub_uint8_t sorted[8];
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+ grub_uint8_t sorted[GRUB_JFS_INODE_INLINE_ENTRIES];
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} header;
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- struct grub_jfs_leaf_dirent dirents[8];
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+ struct grub_jfs_leaf_dirent dirents[GRUB_JFS_INODE_INLINE_ENTRIES];
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} GRUB_PACKED dir;
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/* Fast symlink. */
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struct
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@@ -453,6 +459,13 @@ grub_jfs_opendir (struct grub_jfs_data *data, struct grub_jfs_inode *inode)
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/* Check if the entire tree is contained within the inode. */
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if (inode->file.tree.flags & GRUB_JFS_TREE_LEAF)
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{
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+ if (inode->dir.header.count > GRUB_JFS_INODE_INLINE_ENTRIES)
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+ {
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+ grub_free (diro);
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+ grub_error (GRUB_ERR_BAD_FS, N_("invalid JFS inode"));
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+ return 0;
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+ }
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+
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diro->leaf = inode->dir.dirents;
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diro->next_leaf = (struct grub_jfs_leaf_next_dirent *) de;
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diro->sorted = inode->dir.header.sorted;
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