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-rw-r--r--fs/ubifs/io.c22
1 files changed, 14 insertions, 8 deletions
diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c
index 01682713af69..e8e632a1dcdf 100644
--- a/fs/ubifs/io.c
+++ b/fs/ubifs/io.c
@@ -29,7 +29,7 @@
29 * would have been wasted for padding to the nearest minimal I/O unit boundary. 29 * would have been wasted for padding to the nearest minimal I/O unit boundary.
30 * Instead, data first goes to the write-buffer and is flushed when the 30 * Instead, data first goes to the write-buffer and is flushed when the
31 * buffer is full or when it is not used for some time (by timer). This is 31 * buffer is full or when it is not used for some time (by timer). This is
32 * similarto the mechanism is used by JFFS2. 32 * similar to the mechanism is used by JFFS2.
33 * 33 *
34 * Write-buffers are defined by 'struct ubifs_wbuf' objects and protected by 34 * Write-buffers are defined by 'struct ubifs_wbuf' objects and protected by
35 * mutexes defined inside these objects. Since sometimes upper-level code 35 * mutexes defined inside these objects. Since sometimes upper-level code
@@ -75,7 +75,7 @@ void ubifs_ro_mode(struct ubifs_info *c, int err)
75 * @lnum: logical eraseblock number 75 * @lnum: logical eraseblock number
76 * @offs: offset within the logical eraseblock 76 * @offs: offset within the logical eraseblock
77 * @quiet: print no messages 77 * @quiet: print no messages
78 * @chk_crc: indicates whether to always check the CRC 78 * @must_chk_crc: indicates whether to always check the CRC
79 * 79 *
80 * This function checks node magic number and CRC checksum. This function also 80 * This function checks node magic number and CRC checksum. This function also
81 * validates node length to prevent UBIFS from becoming crazy when an attacker 81 * validates node length to prevent UBIFS from becoming crazy when an attacker
@@ -83,11 +83,17 @@ void ubifs_ro_mode(struct ubifs_info *c, int err)
83 * node length in the common header could cause UBIFS to read memory outside of 83 * node length in the common header could cause UBIFS to read memory outside of
84 * allocated buffer when checking the CRC checksum. 84 * allocated buffer when checking the CRC checksum.
85 * 85 *
86 * This function returns zero in case of success %-EUCLEAN in case of bad CRC 86 * This function may skip data nodes CRC checking if @c->no_chk_data_crc is
87 * or magic. 87 * true, which is controlled by corresponding UBIFS mount option. However, if
88 * @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is
89 * checked. Similarly, if @c->always_chk_crc is true, @c->no_chk_data_crc is
90 * ignored and CRC is checked.
91 *
92 * This function returns zero in case of success and %-EUCLEAN in case of bad
93 * CRC or magic.
88 */ 94 */
89int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum, 95int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
90 int offs, int quiet, int chk_crc) 96 int offs, int quiet, int must_chk_crc)
91{ 97{
92 int err = -EINVAL, type, node_len; 98 int err = -EINVAL, type, node_len;
93 uint32_t crc, node_crc, magic; 99 uint32_t crc, node_crc, magic;
@@ -123,9 +129,9 @@ int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
123 node_len > c->ranges[type].max_len) 129 node_len > c->ranges[type].max_len)
124 goto out_len; 130 goto out_len;
125 131
126 if (!chk_crc && type == UBIFS_DATA_NODE && !c->always_chk_crc) 132 if (!must_chk_crc && type == UBIFS_DATA_NODE && !c->always_chk_crc &&
127 if (c->no_chk_data_crc) 133 c->no_chk_data_crc)
128 return 0; 134 return 0;
129 135
130 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8); 136 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
131 node_crc = le32_to_cpu(ch->crc); 137 node_crc = le32_to_cpu(ch->crc);