From: Erick Archer erick.archer@gmx.com
As noted in the "Deprecated Interfaces, Language Features, Attributes, and Conventions" documentation [1], size calculations (especially multiplication) should not be performed in memory allocator (or similar) function arguments due to the risk of them overflowing. This could lead to values wrapping around and a smaller allocation being made than the caller was expecting. Using those allocations could lead to linear overflows of heap memory and other misbehaviors.
So, use the purpose specific kcalloc() function instead of the argument size * count in the kzalloc() function.
[1] https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arit...
Link: https://lore.kernel.org/linux-trace-kernel/20240115181658.4562-1-erick.arche...
Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Mark Rutland mark.rutland@arm.com Link: https://github.com/KSPP/linux/issues/162 Signed-off-by: Erick Archer erick.archer@gmx.com Reviewed-by: Gustavo A. R. Silva gustavoars@kernel.org Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org --- fs/tracefs/event_inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 10580d6b5012..6795fda2af19 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -97,7 +97,7 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry, /* Preallocate the children mode array if necessary */ if (!(dentry->d_inode->i_mode & S_IFDIR)) { if (!ei->entry_attrs) { - ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries, + ei->entry_attrs = kcalloc(ei->nr_entries, sizeof(*ei->entry_attrs), GFP_NOFS); if (!ei->entry_attrs) { ret = -ENOMEM; @@ -874,7 +874,7 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode }
if (size) { - ei->d_children = kzalloc(sizeof(*ei->d_children) * size, GFP_KERNEL); + ei->d_children = kcalloc(size, sizeof(*ei->d_children), GFP_KERNEL); if (!ei->d_children) { kfree_const(ei->name); kfree(ei); @@ -941,7 +941,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry goto fail;
if (size) { - ei->d_children = kzalloc(sizeof(*ei->d_children) * size, GFP_KERNEL); + ei->d_children = kcalloc(size, sizeof(*ei->d_children), GFP_KERNEL); if (!ei->d_children) goto fail; }