| Message ID | 20230307230148.3735684-1-jacob.e.keller@intel.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | a23c82e006db2f073fb65da8762f63735a510409 |
| Delegated to: | Kalle Valo |
| Headers | show |
| Series | [v2] wifi: ipw2x00: convert ipw_fw_error->elem to flexible array[] | expand |
Jacob Keller <jacob.e.keller@intel.com> wrote: > The ipw_fw_error structure contains a payload[] flexible array as well as > two pointers to this array area, ->elem, and ->log. The total size of the > allocated structure is computed without use of the <linux/overflow.h> > macros. > > There's no reason to keep both a payload[] and an extra pointer to both the > elem and log members. Convert the elem pointer member into the flexible > array member, removing payload. > > Fix the allocation of the ipw_fw_error structure to use size_add(), > struct_size(), and array_size() to compute the allocation. This ensures > that any overflow saturates at SIZE_MAX rather than overflowing and > potentially allowing an undersized allocation. > > Before the structure change, the layout of ipw_fw_error was: > > struct ipw_fw_error { > long unsigned int jiffies; /* 0 8 */ > u32 status; /* 8 4 */ > u32 config; /* 12 4 */ > u32 elem_len; /* 16 4 */ > u32 log_len; /* 20 4 */ > struct ipw_error_elem * elem; /* 24 8 */ > struct ipw_event * log; /* 32 8 */ > u8 payload[]; /* 40 0 */ > > /* size: 40, cachelines: 1, members: 8 */ > /* last cacheline: 40 bytes */ > }; > > After this change, the layout is now: > > struct ipw_fw_error { > long unsigned int jiffies; /* 0 8 */ > u32 status; /* 8 4 */ > u32 config; /* 12 4 */ > u32 elem_len; /* 16 4 */ > u32 log_len; /* 20 4 */ > struct ipw_event * log; /* 24 8 */ > struct ipw_error_elem elem[]; /* 32 0 */ > > /* size: 32, cachelines: 1, members: 7 */ > /* last cacheline: 32 bytes */ > }; > > This saves a total of 8 bytes for every ipw_fw_error allocation, and > removes the risk of a potential overflow on the allocation. > > Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> > Cc: Stanislav Yakovlev <stas.yakovlev@gmail.com> Patch applied to wireless-next.git, thanks. a23c82e006db wifi: ipw2x00: convert ipw_fw_error->elem to flexible array[]
diff --git a/drivers/net/wireless/intel/ipw2x00/ipw2200.c b/drivers/net/wireless/intel/ipw2x00/ipw2200.c index d382f2017325..b91b1a2d0be7 100644 --- a/drivers/net/wireless/intel/ipw2x00/ipw2200.c +++ b/drivers/net/wireless/intel/ipw2x00/ipw2200.c @@ -1234,9 +1234,9 @@ static struct ipw_fw_error *ipw_alloc_error_log(struct ipw_priv *priv) u32 base = ipw_read32(priv, IPW_ERROR_LOG); u32 elem_len = ipw_read_reg32(priv, base); - error = kmalloc(sizeof(*error) + - sizeof(*error->elem) * elem_len + - sizeof(*error->log) * log_len, GFP_ATOMIC); + error = kmalloc(size_add(struct_size(error, elem, elem_len), + array_size(sizeof(*error->log), log_len)), + GFP_ATOMIC); if (!error) { IPW_ERROR("Memory allocation for firmware error log " "failed.\n"); @@ -1247,7 +1247,6 @@ static struct ipw_fw_error *ipw_alloc_error_log(struct ipw_priv *priv) error->config = priv->config; error->elem_len = elem_len; error->log_len = log_len; - error->elem = (struct ipw_error_elem *)error->payload; error->log = (struct ipw_event *)(error->elem + elem_len); ipw_capture_event_log(priv, log_len, error->log); diff --git a/drivers/net/wireless/intel/ipw2x00/ipw2200.h b/drivers/net/wireless/intel/ipw2x00/ipw2200.h index 09ddd21608d4..8ebf09121e17 100644 --- a/drivers/net/wireless/intel/ipw2x00/ipw2200.h +++ b/drivers/net/wireless/intel/ipw2x00/ipw2200.h @@ -1106,9 +1106,8 @@ struct ipw_fw_error { /* XXX */ u32 config; u32 elem_len; u32 log_len; - struct ipw_error_elem *elem; struct ipw_event *log; - u8 payload[]; + struct ipw_error_elem elem[]; } __packed; #ifdef CONFIG_IPW2200_PROMISCUOUS
The ipw_fw_error structure contains a payload[] flexible array as well as two pointers to this array area, ->elem, and ->log. The total size of the allocated structure is computed without use of the <linux/overflow.h> macros. There's no reason to keep both a payload[] and an extra pointer to both the elem and log members. Convert the elem pointer member into the flexible array member, removing payload. Fix the allocation of the ipw_fw_error structure to use size_add(), struct_size(), and array_size() to compute the allocation. This ensures that any overflow saturates at SIZE_MAX rather than overflowing and potentially allowing an undersized allocation. Before the structure change, the layout of ipw_fw_error was: struct ipw_fw_error { long unsigned int jiffies; /* 0 8 */ u32 status; /* 8 4 */ u32 config; /* 12 4 */ u32 elem_len; /* 16 4 */ u32 log_len; /* 20 4 */ struct ipw_error_elem * elem; /* 24 8 */ struct ipw_event * log; /* 32 8 */ u8 payload[]; /* 40 0 */ /* size: 40, cachelines: 1, members: 8 */ /* last cacheline: 40 bytes */ }; After this change, the layout is now: struct ipw_fw_error { long unsigned int jiffies; /* 0 8 */ u32 status; /* 8 4 */ u32 config; /* 12 4 */ u32 elem_len; /* 16 4 */ u32 log_len; /* 20 4 */ struct ipw_event * log; /* 24 8 */ struct ipw_error_elem elem[]; /* 32 0 */ /* size: 32, cachelines: 1, members: 7 */ /* last cacheline: 32 bytes */ }; This saves a total of 8 bytes for every ipw_fw_error allocation, and removes the risk of a potential overflow on the allocation. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Cc: Stanislav Yakovlev <stas.yakovlev@gmail.com> --- This was discovered by a coccinelle patch I developed, and submitted at: https://lore.kernel.org/all/20230227202428.3657443-1-jacob.e.keller@intel.com/ V1: https://lore.kernel.org/linux-wireless/99a9d4a2-d032-1c9d-90c6-3a68f6b3a092@intel.com/ Changes since v1 * Split series into individual postings to avoid confusion about dependency drivers/net/wireless/intel/ipw2x00/ipw2200.c | 7 +++---- drivers/net/wireless/intel/ipw2x00/ipw2200.h | 3 +-- 2 files changed, 4 insertions(+), 6 deletions(-) base-commit: 8f9850dd8d23c1290cb642ce9548a440da5771ec