[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20240813070707.34203-1-thorsten.blum@toblux.com>
Date: Tue, 13 Aug 2024 09:07:07 +0200
From: Thorsten Blum <thorsten.blum@...lux.com>
To: tytso@....edu,
adilger.kernel@...ger.ca,
kees@...nel.org,
gustavoars@...nel.org
Cc: linux-ext4@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-hardening@...r.kernel.org,
Thorsten Blum <thorsten.blum@...lux.com>
Subject: [RESEND PATCH v4] ext4: Annotate struct ext4_xattr_inode_array with __counted_by()
Add the __counted_by compiler attribute to the flexible array member
inodes to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and
CONFIG_FORTIFY_SOURCE.
Remove the now obsolete comment on the count field.
In ext4_expand_inode_array(), use struct_size() instead of offsetof()
and remove the local variable count. Increment the count field before
adding a new inode to the inodes array.
Compile-tested only.
Signed-off-by: Thorsten Blum <thorsten.blum@...lux.com>
---
Changes in v2:
- Adjust ext4_expand_inode_array() as suggested by Gustavo A. R. Silva
- Use struct_size() and struct_size_t() instead of offsetof()
- Link to v1: https://lore.kernel.org/linux-kernel/20240729110454.346918-3-thorsten.blum@toblux.com/
Changes in v3:
- Use struct_size() instead of struct_size_t() as suggested by Kees Cook
- Remove the local variable count as suggested by Gustavo A. R. Silva
- Increment count before adding a new inode as suggested by Gustavo
- Link to v2: https://lore.kernel.org/linux-kernel/20240730172301.231867-4-thorsten.blum@toblux.com/
Changes in v4:
- Remove unnecessary count assignment and adjust copying the whole
struct as suggested by Gustavo
- Link to v3: https://lore.kernel.org/linux-kernel/20240730205509.323320-3-thorsten.blum@toblux.com/
---
fs/ext4/xattr.c | 22 ++++++++++------------
fs/ext4/xattr.h | 4 ++--
2 files changed, 12 insertions(+), 14 deletions(-)
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 46ce2f21fef9..263567d4e13d 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2879,33 +2879,31 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
if (*ea_inode_array == NULL) {
/*
* Start with 15 inodes, so it fits into a power-of-two size.
- * If *ea_inode_array is NULL, this is essentially offsetof()
*/
- (*ea_inode_array) =
- kmalloc(offsetof(struct ext4_xattr_inode_array,
- inodes[EIA_MASK]),
- GFP_NOFS);
+ (*ea_inode_array) = kmalloc(
+ struct_size(*ea_inode_array, inodes, EIA_MASK),
+ GFP_NOFS);
if (*ea_inode_array == NULL)
return -ENOMEM;
(*ea_inode_array)->count = 0;
} else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
/* expand the array once all 15 + n * 16 slots are full */
struct ext4_xattr_inode_array *new_array = NULL;
- int count = (*ea_inode_array)->count;
- /* if new_array is NULL, this is essentially offsetof() */
new_array = kmalloc(
- offsetof(struct ext4_xattr_inode_array,
- inodes[count + EIA_INCR]),
- GFP_NOFS);
+ struct_size(*ea_inode_array, inodes,
+ (*ea_inode_array)->count + EIA_INCR),
+ GFP_NOFS);
if (new_array == NULL)
return -ENOMEM;
memcpy(new_array, *ea_inode_array,
- offsetof(struct ext4_xattr_inode_array, inodes[count]));
+ struct_size(*ea_inode_array, inodes,
+ (*ea_inode_array)->count));
kfree(*ea_inode_array);
*ea_inode_array = new_array;
}
- (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
+ (*ea_inode_array)->count++;
+ (*ea_inode_array)->inodes[(*ea_inode_array)->count - 1] = inode;
return 0;
}
diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
index bd97c4aa8177..e14fb19dc912 100644
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -130,8 +130,8 @@ struct ext4_xattr_ibody_find {
};
struct ext4_xattr_inode_array {
- unsigned int count; /* # of used items in the array */
- struct inode *inodes[];
+ unsigned int count;
+ struct inode *inodes[] __counted_by(count);
};
extern const struct xattr_handler ext4_xattr_user_handler;
--
2.46.0
Powered by blists - more mailing lists