5.4-stable review patch. If anyone has any objections, please let me know.
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From: Erick Archer erick.archer@outlook.com
[ Upstream commit e5c5f3596de224422561d48eba6ece5210d967b3 ]
This is an effort to get rid of all multiplications from allocation functions in order to prevent integer overflows [1][2].
As the "ids" variable is a pointer to "struct sctp_assoc_ids" and this structure ends in a flexible array:
struct sctp_assoc_ids { [...] sctp_assoc_t gaids_assoc_id[]; };
the preferred way in the kernel is to use the struct_size() helper to do the arithmetic instead of the calculation "size + size * count" in the kmalloc() function.
Also, refactor the code adding the "ids_size" variable to avoid sizing twice.
This way, the code is more readable and safer.
This code was detected with the help of Coccinelle, and audited and modified manually.
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-ar... [1] Link: https://github.com/KSPP/linux/issues/160 [2] Signed-off-by: Erick Archer erick.archer@outlook.com Acked-by: Xin Long lucien.xin@gmail.com Reviewed-by: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/PAXPR02MB724871DB78375AB06B5171C88B152@PAXPR02MB72... Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/sctp/socket.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c index cbcbc92748ba9..c188a0acfa594 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -7158,6 +7158,7 @@ static int sctp_getsockopt_assoc_ids(struct sock *sk, int len, struct sctp_sock *sp = sctp_sk(sk); struct sctp_association *asoc; struct sctp_assoc_ids *ids; + size_t ids_size; u32 num = 0;
if (sctp_style(sk, TCP)) @@ -7170,11 +7171,11 @@ static int sctp_getsockopt_assoc_ids(struct sock *sk, int len, num++; }
- if (len < sizeof(struct sctp_assoc_ids) + sizeof(sctp_assoc_t) * num) + ids_size = struct_size(ids, gaids_assoc_id, num); + if (len < ids_size) return -EINVAL;
- len = sizeof(struct sctp_assoc_ids) + sizeof(sctp_assoc_t) * num; - + len = ids_size; ids = kmalloc(len, GFP_USER | __GFP_NOWARN); if (unlikely(!ids)) return -ENOMEM;