From 8ade3356b25ab2522892a21832a709e7ad5f8168 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 28 Feb 2024 09:55:42 +0100 Subject: [PATCH] wifi: cfg80211: allow cfg80211_defragment_element() without output If we just want to determine the length of the fragmented data, we basically need the same logic, and really we want it to be _literally_ the same logic, so it cannot be out of sync in any way. Allow calling cfg80211_defragment_element() without an output buffer, where it then just returns the required output size. Also add this to the tests, just to exercise it, using the pre-calculated length to really do the defragmentation, which checks that this is sufficient. Reviewed-by: Miriam Rachel Korenblit Reviewed-by: Benjamin Berg Link: https://msgid.link/20240228095718.6d6565b9e3f2.Ib441903f4b8644ba04b1c766f90580ee6f54fc66@changeid Signed-off-by: Johannes Berg --- include/net/cfg80211.h | 4 ++-- net/wireless/scan.c | 27 ++++++++++++++++++--------- net/wireless/tests/fragmentation.c | 30 +++++++++++++++++++++++++----- 3 files changed, 45 insertions(+), 16 deletions(-) diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index 53653d234d39..2e2be4fd2bb6 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -6908,8 +6908,8 @@ bool cfg80211_iter_rnr(const u8 *elems, size_t elems_len, * @elem: the element to defragment * @ies: elements where @elem is contained * @ieslen: length of @ies - * @data: buffer to store element data - * @data_len: length of @data + * @data: buffer to store element data, or %NULL to just determine size + * @data_len: length of @data, or 0 * @frag_id: the element ID of fragments * * Return: length of @data, or -EINVAL on error diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 9377a43aa5f7..5a5dd3ce497f 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -2504,16 +2504,22 @@ ssize_t cfg80211_defragment_element(const struct element *elem, const u8 *ies, if (elem->id == WLAN_EID_EXTENSION) { copied = elem->datalen - 1; - if (copied > data_len) - return -ENOSPC; - memmove(data, elem->data + 1, copied); + if (data) { + if (copied > data_len) + return -ENOSPC; + + memmove(data, elem->data + 1, copied); + } } else { copied = elem->datalen; - if (copied > data_len) - return -ENOSPC; - memmove(data, elem->data, copied); + if (data) { + if (copied > data_len) + return -ENOSPC; + + memmove(data, elem->data, copied); + } } /* Fragmented elements must have 255 bytes */ @@ -2532,10 +2538,13 @@ ssize_t cfg80211_defragment_element(const struct element *elem, const u8 *ies, elem_datalen = elem->datalen; - if (copied + elem_datalen > data_len) - return -ENOSPC; + if (data) { + if (copied + elem_datalen > data_len) + return -ENOSPC; + + memmove(data + copied, elem->data, elem_datalen); + } - memmove(data + copied, elem->data, elem_datalen); copied += elem_datalen; /* Only the last fragment may be short */ diff --git a/net/wireless/tests/fragmentation.c b/net/wireless/tests/fragmentation.c index 49a339ca8880..411fae18cd88 100644 --- a/net/wireless/tests/fragmentation.c +++ b/net/wireless/tests/fragmentation.c @@ -2,7 +2,7 @@ /* * KUnit tests for element fragmentation * - * Copyright (C) 2023 Intel Corporation + * Copyright (C) 2023-2024 Intel Corporation */ #include #include @@ -27,7 +27,12 @@ static void defragment_0(struct kunit *test) ret = cfg80211_defragment_element((void *)input, input, sizeof(input), - data, sizeof(input), + NULL, 0, + WLAN_EID_FRAGMENT); + KUNIT_EXPECT_EQ(test, ret, 253); + ret = cfg80211_defragment_element((void *)input, + input, sizeof(input), + data, ret, WLAN_EID_FRAGMENT); KUNIT_EXPECT_EQ(test, ret, 253); KUNIT_EXPECT_MEMEQ(test, data, input + 3, 253); @@ -63,7 +68,12 @@ static void defragment_1(struct kunit *test) ret = cfg80211_defragment_element((void *)input, input, sizeof(input), - data, sizeof(input), + NULL, 0, + WLAN_EID_FRAGMENT); + KUNIT_EXPECT_EQ(test, ret, 254 + 7); + ret = cfg80211_defragment_element((void *)input, + input, sizeof(input), + data, ret, WLAN_EID_FRAGMENT); /* this means the last fragment was not used */ KUNIT_EXPECT_EQ(test, ret, 254 + 7); @@ -106,10 +116,15 @@ static void defragment_2(struct kunit *test) ret = cfg80211_defragment_element((void *)input, input, sizeof(input), - data, sizeof(input), + NULL, 0, WLAN_EID_FRAGMENT); /* this means the last fragment was not used */ KUNIT_EXPECT_EQ(test, ret, 254 + 255 + 1); + ret = cfg80211_defragment_element((void *)input, + input, sizeof(input), + data, ret, + WLAN_EID_FRAGMENT); + KUNIT_EXPECT_EQ(test, ret, 254 + 255 + 1); KUNIT_EXPECT_MEMEQ(test, data, input + 3, 254); KUNIT_EXPECT_MEMEQ(test, data + 254, input + 257 + 2, 255); KUNIT_EXPECT_MEMEQ(test, data + 254 + 255, input + 2 * 257 + 2, 1); @@ -134,7 +149,12 @@ static void defragment_at_end(struct kunit *test) ret = cfg80211_defragment_element((void *)input, input, sizeof(input), - data, sizeof(input), + NULL, 0, + WLAN_EID_FRAGMENT); + KUNIT_EXPECT_EQ(test, ret, 254 + 7); + ret = cfg80211_defragment_element((void *)input, + input, sizeof(input), + data, ret, WLAN_EID_FRAGMENT); KUNIT_EXPECT_EQ(test, ret, 254 + 7); KUNIT_EXPECT_MEMEQ(test, data, input + 3, 254);