5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yichong Chen commit 2602b79c5b3e2f6fce12e38a670f8e3fda4e46a2 upstream. ecryptfs_parse_packet_set() receives a pointer into the file header, but it calculates the remaining packet buffer size from PAGE_SIZE - 8. For version 1 headers the packet set starts later in the header, so this can overstate the available buffer. Pass the actual packet set buffer length from the caller and calculate per-packet limits from the remaining bytes in that buffer. Recompute the remaining length after consuming a tag 3 packet before parsing the following tag 11 packet. Fixes: 237fead61998 ("[PATCH] ecryptfs: fs/Makefile and fs/Kconfig") Cc: Signed-off-by: Yichong Chen Signed-off-by: Tyler Hicks Signed-off-by: Greg Kroah-Hartman --- fs/ecryptfs/crypto.c | 2 +- fs/ecryptfs/ecryptfs_kernel.h | 3 ++- fs/ecryptfs/keystore.c | 23 ++++++++++++++++++++--- 3 files changed, 23 insertions(+), 5 deletions(-) --- a/fs/ecryptfs/crypto.c +++ b/fs/ecryptfs/crypto.c @@ -1309,7 +1309,7 @@ static int ecryptfs_read_headers_virt(ch } else set_default_header_data(crypt_stat); rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset), - ecryptfs_dentry); + PAGE_SIZE - offset, ecryptfs_dentry); out: return rc; } --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -605,7 +605,8 @@ int ecryptfs_generate_key_packet_set(cha size_t *len, size_t max); int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, - unsigned char *src, struct dentry *ecryptfs_dentry); + unsigned char *src, size_t src_size, + struct dentry *ecryptfs_dentry); int ecryptfs_truncate(struct dentry *dentry, loff_t new_length); ssize_t ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode, --- a/fs/ecryptfs/keystore.c +++ b/fs/ecryptfs/keystore.c @@ -1742,6 +1742,7 @@ out: * ecryptfs_parse_packet_set * @crypt_stat: The cryptographic context * @src: Virtual address of region of memory containing the packets + * @src_size: Size of the packet set buffer * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set * * Get crypt_stat to have the file's session key if the requisite key @@ -1752,7 +1753,7 @@ out: * conditions. */ int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, - unsigned char *src, + unsigned char *src, size_t src_size, struct dentry *ecryptfs_dentry) { size_t i = 0; @@ -1776,7 +1777,11 @@ int ecryptfs_parse_packet_set(struct ecr * added the our &auth_tok_list */ next_packet_is_auth_tok_packet = 1; while (next_packet_is_auth_tok_packet) { - size_t max_packet_size = ((PAGE_SIZE - 8) - i); + size_t max_packet_size; + + if (i >= src_size) + break; + max_packet_size = src_size - i; switch (src[i]) { case ECRYPTFS_TAG_3_PACKET_TYPE: @@ -1791,12 +1796,16 @@ int ecryptfs_parse_packet_set(struct ecr goto out_wipe_list; } i += packet_size; + if (i > src_size) { + rc = -EIO; + goto out_wipe_list; + } rc = parse_tag_11_packet((unsigned char *)&src[i], sig_tmp_space, ECRYPTFS_SIG_SIZE, &tag_11_contents_size, &tag_11_packet_size, - max_packet_size); + src_size - i); if (rc) { ecryptfs_printk(KERN_ERR, "No valid " "(ecryptfs-specific) literal " @@ -1808,6 +1817,10 @@ int ecryptfs_parse_packet_set(struct ecr goto out_wipe_list; } i += tag_11_packet_size; + if (i > src_size) { + rc = -EIO; + goto out_wipe_list; + } if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { ecryptfs_printk(KERN_ERR, "Expected " "signature of size [%d]; " @@ -1835,6 +1848,10 @@ int ecryptfs_parse_packet_set(struct ecr goto out_wipe_list; } i += packet_size; + if (i > src_size) { + rc = -EIO; + goto out_wipe_list; + } crypt_stat->flags |= ECRYPTFS_ENCRYPTED; break; case ECRYPTFS_TAG_11_PACKET_TYPE: