133 lines
4.4 KiB
Diff
133 lines
4.4 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
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Date: Wed, 6 Apr 2022 18:49:09 +0530
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Subject: [PATCH] fs/f2fs: Do not read past the end of nat bitmap
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A corrupt f2fs filesystem could have a block offset or a bitmap
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offset that would cause us to read beyond the bounds of the nat
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bitmap.
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Introduce the nat_bitmap_size member in grub_f2fs_data which holds
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the size of nat bitmap.
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Set the size when loading the nat bitmap in nat_bitmap_ptr(), and
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catch when an invalid offset would create a pointer past the end of
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the allocated space.
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Check against the bitmap size in grub_f2fs_test_bit() test bit to avoid
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reading past the end of the nat bitmap.
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Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
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Signed-off-by: Daniel Axtens <dja@axtens.net>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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(cherry picked from commit 62d63d5e38c67a6e349148bf7cb87c560e935a7e)
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---
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grub-core/fs/f2fs.c | 33 +++++++++++++++++++++++++++------
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1 file changed, 27 insertions(+), 6 deletions(-)
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diff --git a/grub-core/fs/f2fs.c b/grub-core/fs/f2fs.c
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index 63702214b0..8898b235e0 100644
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--- a/grub-core/fs/f2fs.c
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+++ b/grub-core/fs/f2fs.c
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@@ -122,6 +122,7 @@ GRUB_MOD_LICENSE ("GPLv3+");
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#define F2FS_INLINE_DOTS 0x10 /* File having implicit dot dentries. */
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#define MAX_VOLUME_NAME 512
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+#define MAX_NAT_BITMAP_SIZE 3900
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enum FILE_TYPE
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{
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@@ -183,7 +184,7 @@ struct grub_f2fs_checkpoint
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grub_uint32_t checksum_offset;
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grub_uint64_t elapsed_time;
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grub_uint8_t alloc_type[MAX_ACTIVE_LOGS];
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- grub_uint8_t sit_nat_version_bitmap[3900];
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+ grub_uint8_t sit_nat_version_bitmap[MAX_NAT_BITMAP_SIZE];
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grub_uint32_t checksum;
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} GRUB_PACKED;
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@@ -302,6 +303,7 @@ struct grub_f2fs_data
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struct grub_f2fs_nat_journal nat_j;
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char *nat_bitmap;
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+ grub_uint32_t nat_bitmap_size;
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grub_disk_t disk;
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struct grub_f2fs_node *inode;
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@@ -377,15 +379,20 @@ sum_blk_addr (struct grub_f2fs_data *data, int base, int type)
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}
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static void *
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-nat_bitmap_ptr (struct grub_f2fs_data *data)
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+nat_bitmap_ptr (struct grub_f2fs_data *data, grub_uint32_t *nat_bitmap_size)
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{
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struct grub_f2fs_checkpoint *ckpt = &data->ckpt;
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grub_uint32_t offset;
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+ *nat_bitmap_size = MAX_NAT_BITMAP_SIZE;
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if (grub_le_to_cpu32 (data->sblock.cp_payload) > 0)
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return ckpt->sit_nat_version_bitmap;
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offset = grub_le_to_cpu32 (ckpt->sit_ver_bitmap_bytesize);
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+ if (offset >= MAX_NAT_BITMAP_SIZE)
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+ return NULL;
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+
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+ *nat_bitmap_size = *nat_bitmap_size - offset;
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return ckpt->sit_nat_version_bitmap + offset;
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}
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@@ -438,11 +445,15 @@ grub_f2fs_crc_valid (grub_uint32_t blk_crc, void *buf, const grub_uint32_t len)
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}
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static int
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-grub_f2fs_test_bit (grub_uint32_t nr, const char *p)
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+grub_f2fs_test_bit (grub_uint32_t nr, const char *p, grub_uint32_t len)
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{
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int mask;
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+ grub_uint32_t shifted_nr = (nr >> 3);
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- p += (nr >> 3);
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+ if (shifted_nr >= len)
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+ return -1;
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+
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+ p += shifted_nr;
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mask = 1 << (7 - (nr & 0x07));
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return mask & *p;
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@@ -662,6 +673,7 @@ get_node_blkaddr (struct grub_f2fs_data *data, grub_uint32_t nid)
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grub_uint32_t seg_off, block_off, entry_off, block_addr;
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grub_uint32_t blkaddr = 0;
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grub_err_t err;
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+ int result_bit;
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err = get_blkaddr_from_nat_journal (data, nid, &blkaddr);
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if (err != GRUB_ERR_NONE)
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@@ -682,8 +694,15 @@ get_node_blkaddr (struct grub_f2fs_data *data, grub_uint32_t nid)
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((seg_off * data->blocks_per_seg) << 1) +
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(block_off & (data->blocks_per_seg - 1));
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- if (grub_f2fs_test_bit (block_off, data->nat_bitmap))
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+ result_bit = grub_f2fs_test_bit (block_off, data->nat_bitmap,
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+ data->nat_bitmap_size);
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+ if (result_bit > 0)
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block_addr += data->blocks_per_seg;
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+ else if (result_bit == -1)
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+ {
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+ grub_free (nat_block);
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+ return 0;
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+ }
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err = grub_f2fs_block_read (data, block_addr, nat_block);
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if (err)
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@@ -833,7 +852,9 @@ grub_f2fs_mount (grub_disk_t disk)
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if (err)
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goto fail;
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- data->nat_bitmap = nat_bitmap_ptr (data);
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+ data->nat_bitmap = nat_bitmap_ptr (data, &data->nat_bitmap_size);
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+ if (data->nat_bitmap == NULL)
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+ goto fail;
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err = get_nat_journal (data);
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if (err)
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