3.16.65-rc1 review patch. If anyone has any objections, please let me know.
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From: Eric Biggers ebiggers@google.com
commit 0ac6b8fb23c724b015d9ca70a89126e8d1563166 upstream.
CRYPTO_MSG_GETALG in NLM_F_DUMP mode sometimes doesn't return all registered crypto algorithms, because it doesn't support incremental dumps. crypto_dump_report() only permits itself to be called once, yet the netlink subsystem allocates at most ~64 KiB for the skb being dumped to. Thus only the first recvmsg() returns data, and it may only include a subset of the crypto algorithms even if the user buffer passed to recvmsg() is large enough to hold all of them.
Fix this by using one of the arguments in the netlink_callback structure to keep track of the current position in the algorithm list. Then userspace can do multiple recvmsg() on the socket after sending the dump request. This is the way netlink dumps work elsewhere in the kernel; it's unclear why this was different (probably just an oversight).
Also fix an integer overflow when calculating the dump buffer size hint.
Fixes: a38f7907b926 ("crypto: Add userspace configuration API") Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au [bwh: Backported to 3.16: adjust filename] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- crypto/crypto_user.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-)
--- a/crypto/crypto_user.c +++ b/crypto/crypto_user.c @@ -226,30 +226,33 @@ static int crypto_report(struct sk_buff
static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb) { - struct crypto_alg *alg; + const size_t start_pos = cb->args[0]; + size_t pos = 0; struct crypto_dump_info info; - int err; - - if (cb->args[0]) - goto out; - - cb->args[0] = 1; + struct crypto_alg *alg; + int res;
info.in_skb = cb->skb; info.out_skb = skb; info.nlmsg_seq = cb->nlh->nlmsg_seq; info.nlmsg_flags = NLM_F_MULTI;
+ down_read(&crypto_alg_sem); list_for_each_entry(alg, &crypto_alg_list, cra_list) { - err = crypto_report_alg(alg, &info); - if (err) - goto out_err; + if (pos >= start_pos) { + res = crypto_report_alg(alg, &info); + if (res == -EMSGSIZE) + break; + if (res) + goto out; + } + pos++; } - + cb->args[0] = pos; + res = skb->len; out: - return skb->len; -out_err: - return err; + up_read(&crypto_alg_sem); + return res; }
static int crypto_dump_report_done(struct netlink_callback *cb) @@ -478,7 +481,7 @@ static int crypto_user_rcv_msg(struct sk if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) && (nlh->nlmsg_flags & NLM_F_DUMP))) { struct crypto_alg *alg; - u16 dump_alloc = 0; + unsigned long dump_alloc = 0;
if (link->dump == NULL) return -EINVAL; @@ -486,16 +489,16 @@ static int crypto_user_rcv_msg(struct sk down_read(&crypto_alg_sem); list_for_each_entry(alg, &crypto_alg_list, cra_list) dump_alloc += CRYPTO_REPORT_MAXSIZE; + up_read(&crypto_alg_sem);
{ struct netlink_dump_control c = { .dump = link->dump, .done = link->done, - .min_dump_alloc = dump_alloc, + .min_dump_alloc = min(dump_alloc, 65535UL), }; err = netlink_dump_start(crypto_nlsk, skb, nlh, &c); } - up_read(&crypto_alg_sem);
return err; }