From patchwork Wed Aug 4 18:23:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. 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R. Silva" To: "David S. Miller" , Hideaki YOSHIFUJI , David Ahern , Jakub Kicinski Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH][next] net/ipv4: Revert use of struct_size() helper Message-ID: <20210804182325.GA11752@embeddedor> MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Revert the use of structr_size() and stay with IP_MSFILTER_SIZE() for now, as in this case, the size of struct ip_msfilter didn't change with the addition of the flexible array imsf_slist_flex[]. So, if we use struct_size() we will be allocating and calculating the size of struct ip_msfilter with one too many items for imsf_slist_flex[]. We might use struct_size() in the future, but for now let's stay with IP_MSFILTER_SIZE(). Fixes: 2d3e5caf96b9 ("net/ipv4: Replace one-element array with flexible-array member") Signed-off-by: Gustavo A. R. Silva --- net/ipv4/igmp.c | 4 ++-- net/ipv4/ip_sockglue.c | 12 +++++------- 2 files changed, 7 insertions(+), 9 deletions(-) diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index a5f4ecb02e97..c2d477eb6825 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -2553,8 +2553,8 @@ int ip_mc_msfget(struct sock *sk, struct ip_msfilter *msf, copycount = count < msf->imsf_numsrc ? count : msf->imsf_numsrc; len = flex_array_size(psl, sl_addr, copycount); msf->imsf_numsrc = count; - if (put_user(struct_size(optval, imsf_slist_flex, copycount), optlen) || - copy_to_user(optval, msf, struct_size(optval, imsf_slist_flex, 0))) { + if (put_user(IP_MSFILTER_SIZE(copycount), optlen) || + copy_to_user(optval, msf, IP_MSFILTER_SIZE(0))) { return -EFAULT; } if (len && diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index bbe660b84a91..468969c75708 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -667,7 +667,7 @@ static int set_mcast_msfilter(struct sock *sk, int ifindex, struct sockaddr_in *psin; int err, i; - msf = kmalloc(struct_size(msf, imsf_slist_flex, numsrc), GFP_KERNEL); + msf = kmalloc(IP_MSFILTER_SIZE(numsrc), GFP_KERNEL); if (!msf) return -ENOBUFS; @@ -1228,7 +1228,7 @@ static int do_ip_setsockopt(struct sock *sk, int level, int optname, { struct ip_msfilter *msf; - if (optlen < struct_size(msf, imsf_slist_flex, 0)) + if (optlen < IP_MSFILTER_SIZE(0)) goto e_inval; if (optlen > sysctl_optmem_max) { err = -ENOBUFS; @@ -1246,8 +1246,7 @@ static int do_ip_setsockopt(struct sock *sk, int level, int optname, err = -ENOBUFS; break; } - if (struct_size(msf, imsf_slist_flex, msf->imsf_numsrc) > - optlen) { + if (IP_MSFILTER_SIZE(msf->imsf_numsrc) > optlen) { kfree(msf); err = -EINVAL; break; @@ -1660,12 +1659,11 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname, { struct ip_msfilter msf; - if (len < struct_size(&msf, imsf_slist_flex, 0)) { + if (len < IP_MSFILTER_SIZE(0)) { err = -EINVAL; goto out; } - if (copy_from_user(&msf, optval, - struct_size(&msf, imsf_slist_flex, 0))) { + if (copy_from_user(&msf, optval, IP_MSFILTER_SIZE(0))) { err = -EFAULT; goto out; }