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ext4 crypto: clean up error handling in ext4_fname_setup_filename 

Fix a potential memory leak where fname->crypto_buf.name wouldn't get
freed in some error paths, and also make the error handling easier to
understand/audit.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2015-05-31 13:35:22 -04:00
parent d87f6d78e9
commit 82d0d3e7e6
1 changed files with 16 additions and 19 deletions
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35
fs/ext4/crypto_fname.c
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@ -401,7 +401,7 @@ int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
((iname->name[1] == '.') && (iname->len == 2))))) {
fname->disk_name.name = (unsigned char *) iname->name;
fname->disk_name.len = iname->len;
goto out;
return 0;
}
ret = ext4_get_encryption_info(dir);
if (ret)
@ -411,19 +411,16 @@ int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
ret = ext4_fname_crypto_alloc_buffer(dir, iname->len,
&fname->crypto_buf);
if (ret < 0)
goto out;
return ret;
ret = ext4_fname_encrypt(dir, iname, &fname->crypto_buf);
if (ret < 0)
goto out;
goto errout;
fname->disk_name.name = fname->crypto_buf.name;
fname->disk_name.len = fname->crypto_buf.len;
ret = 0;
goto out;
}
if (!lookup) {
ret = -EACCES;
goto out;
return 0;
}
if (!lookup)
return -EACCES;
/* We don't have the key and we are doing a lookup; decode the
* user-supplied name
@ -431,19 +428,17 @@ int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
if (iname->name[0] == '_')
bigname = 1;
if ((bigname && (iname->len != 33)) ||
(!bigname && (iname->len > 43))) {
ret = -ENOENT;
}
(!bigname && (iname->len > 43)))
return -ENOENT;
fname->crypto_buf.name = kmalloc(32, GFP_KERNEL);
if (fname->crypto_buf.name == NULL) {
ret = -ENOMEM;
goto out;
}
if (fname->crypto_buf.name == NULL)
return -ENOMEM;
ret = digest_decode(iname->name + bigname, iname->len - bigname,
fname->crypto_buf.name);
if (ret < 0) {
ret = -ENOENT;
goto out;
goto errout;
}
fname->crypto_buf.len = ret;
if (bigname) {
@ -453,8 +448,10 @@ int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
fname->disk_name.name = fname->crypto_buf.name;
fname->disk_name.len = fname->crypto_buf.len;
}
ret = 0;
out:
return 0;
errout:
kfree(fname->crypto_buf.name);
fname->crypto_buf.name = NULL;
return ret;
}