From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ... --- lib/ts_bm.c | 237 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 237 insertions(+) create mode 100644 lib/ts_bm.c (limited to 'lib/ts_bm.c') diff --git a/lib/ts_bm.c b/lib/ts_bm.c new file mode 100644 index 000000000..676105e84 --- /dev/null +++ b/lib/ts_bm.c @@ -0,0 +1,237 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * lib/ts_bm.c Boyer-Moore text search implementation + * + * Authors: Pablo Neira Ayuso + * + * ========================================================================== + * + * Implements Boyer-Moore string matching algorithm: + * + * [1] A Fast String Searching Algorithm, R.S. Boyer and Moore. + * Communications of the Association for Computing Machinery, + * 20(10), 1977, pp. 762-772. + * https://www.cs.utexas.edu/users/moore/publications/fstrpos.pdf + * + * [2] Handbook of Exact String Matching Algorithms, Thierry Lecroq, 2004 + * http://www-igm.univ-mlv.fr/~lecroq/string/string.pdf + * + * Note: Since Boyer-Moore (BM) performs searches for matchings from right + * to left, it's still possible that a matching could be spread over + * multiple blocks, in that case this algorithm won't find any coincidence. + * + * If you're willing to ensure that such thing won't ever happen, use the + * Knuth-Pratt-Morris (KMP) implementation instead. In conclusion, choose + * the proper string search algorithm depending on your setting. + * + * Say you're using the textsearch infrastructure for filtering, NIDS or + * any similar security focused purpose, then go KMP. Otherwise, if you + * really care about performance, say you're classifying packets to apply + * Quality of Service (QoS) policies, and you don't mind about possible + * matchings spread over multiple fragments, then go BM. + */ + +#include +#include +#include +#include +#include +#include + +/* Alphabet size, use ASCII */ +#define ASIZE 256 + +#if 0 +#define DEBUGP printk +#else +#define DEBUGP(args, format...) +#endif + +struct ts_bm +{ + u8 * pattern; + unsigned int patlen; + unsigned int bad_shift[ASIZE]; + unsigned int good_shift[]; +}; + +static unsigned int matchpat(const u8 *pattern, unsigned int patlen, + const u8 *text, bool icase) +{ + unsigned int i; + + for (i = 0; i < patlen; i++) { + u8 t = *(text-i); + + if (icase) + t = toupper(t); + + if (t != *(pattern-i)) + break; + } + + return i; +} + +static unsigned int bm_find(struct ts_config *conf, struct ts_state *state) +{ + struct ts_bm *bm = ts_config_priv(conf); + unsigned int i, text_len, consumed = state->offset; + const u8 *text; + int bs; + const u8 icase = conf->flags & TS_IGNORECASE; + + for (;;) { + int shift = bm->patlen - 1; + + text_len = conf->get_next_block(consumed, &text, conf, state); + + if (unlikely(text_len == 0)) + break; + + while (shift < text_len) { + DEBUGP("Searching in position %d (%c)\n", + shift, text[shift]); + + i = matchpat(&bm->pattern[bm->patlen-1], bm->patlen, + &text[shift], icase); + if (i == bm->patlen) { + /* London calling... */ + DEBUGP("found!\n"); + return consumed + (shift-(bm->patlen-1)); + } + + bs = bm->bad_shift[text[shift-i]]; + + /* Now jumping to... */ + shift = max_t(int, shift-i+bs, shift+bm->good_shift[i]); + } + consumed += text_len; + } + + return UINT_MAX; +} + +static int subpattern(u8 *pattern, int i, int j, int g) +{ + int x = i+g-1, y = j+g-1, ret = 0; + + while(pattern[x--] == pattern[y--]) { + if (y < 0) { + ret = 1; + break; + } + if (--g == 0) { + ret = pattern[i-1] != pattern[j-1]; + break; + } + } + + return ret; +} + +static void compute_prefix_tbl(struct ts_bm *bm, int flags) +{ + int i, j, g; + + for (i = 0; i < ASIZE; i++) + bm->bad_shift[i] = bm->patlen; + for (i = 0; i < bm->patlen - 1; i++) { + bm->bad_shift[bm->pattern[i]] = bm->patlen - 1 - i; + if (flags & TS_IGNORECASE) + bm->bad_shift[tolower(bm->pattern[i])] + = bm->patlen - 1 - i; + } + + /* Compute the good shift array, used to match reocurrences + * of a subpattern */ + bm->good_shift[0] = 1; + for (i = 1; i < bm->patlen; i++) + bm->good_shift[i] = bm->patlen; + for (i = bm->patlen-1, g = 1; i > 0; g++, i--) { + for (j = i-1; j >= 1-g ; j--) + if (subpattern(bm->pattern, i, j, g)) { + bm->good_shift[g] = bm->patlen-j-g; + break; + } + } +} + +static struct ts_config *bm_init(const void *pattern, unsigned int len, + gfp_t gfp_mask, int flags) +{ + struct ts_config *conf; + struct ts_bm *bm; + int i; + unsigned int prefix_tbl_len; + size_t priv_size; + + /* Zero-length patterns would underflow bm_find()'s initial shift. */ + if (unlikely(!len)) + return ERR_PTR(-EINVAL); + + /* + * bm->pattern is stored immediately after the good_shift[] table. + * Reject lengths that would wrap while sizing either region. + */ + if (unlikely(check_mul_overflow(len, sizeof(*bm->good_shift), + &prefix_tbl_len) || + check_add_overflow(sizeof(*bm), (size_t)len, &priv_size) || + check_add_overflow(priv_size, prefix_tbl_len, &priv_size))) + return ERR_PTR(-EINVAL); + + conf = alloc_ts_config(priv_size, gfp_mask); + if (IS_ERR(conf)) + return conf; + + conf->flags = flags; + bm = ts_config_priv(conf); + bm->patlen = len; + bm->pattern = (u8 *) bm->good_shift + prefix_tbl_len; + if (flags & TS_IGNORECASE) + for (i = 0; i < len; i++) + bm->pattern[i] = toupper(((u8 *)pattern)[i]); + else + memcpy(bm->pattern, pattern, len); + compute_prefix_tbl(bm, flags); + + return conf; +} + +static void *bm_get_pattern(struct ts_config *conf) +{ + struct ts_bm *bm = ts_config_priv(conf); + return bm->pattern; +} + +static unsigned int bm_get_pattern_len(struct ts_config *conf) +{ + struct ts_bm *bm = ts_config_priv(conf); + return bm->patlen; +} + +static struct ts_ops bm_ops = { + .name = "bm", + .find = bm_find, + .init = bm_init, + .get_pattern = bm_get_pattern, + .get_pattern_len = bm_get_pattern_len, + .owner = THIS_MODULE, + .list = LIST_HEAD_INIT(bm_ops.list) +}; + +static int __init init_bm(void) +{ + return textsearch_register(&bm_ops); +} + +static void __exit exit_bm(void) +{ + textsearch_unregister(&bm_ops); +} + +MODULE_DESCRIPTION("Boyer-Moore text search implementation"); +MODULE_LICENSE("GPL"); + +module_init(init_bm); +module_exit(exit_bm); -- cgit v1.3.1