From 22098763a10d9c1340827fcf6edab66f153b27f0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 13 Sep 2026 12:27:00 -0700 Subject: Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Don't destroy user event fields when removal fails User event fields are destroyed before the event is removed from visibility. But that can fail leaving the still visible event with no fields. Move the destroying of the fields to after the event is successfully removed from visibility. - Initialize function graph state is fork before calling copy_exec_state() For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state. If that allocation fails, ftrace_graph_exit_task() will free the tasks ret_stack pointer. Since that pointer is still using the parent's ret_stack, it mistakenly frees the parent's pointer too. Call ftrace_graph_init() on the task first which will NULL out the new tasks's ret_stack and if the copy fails, it will not free anything. - Remove FGRAPH_MAX_INDEX The macro FGRAPH_MAX_INDEX was added but never used. Remove it. - Save ent_size in function graph printing of nested functions The function graph tracer needs to look at the next event to see if the next event is the return of the current function entry. If it is, it prints a single line: ktime_get(); Otherwise it prints it like a nested function: tick_nohz_irq_exit() { ktime_get(); kcpustat_irq_exit(); } In order to look at the next event, it must save the current event so that it has the information to print from it. It saves the event in the iterator descriptor called "ent". What it doesn't save is the ent_size of the event which is now used to know if the function graph arguments are to be printed. The peek doesn't save the size so the size used happens to be that of the size of the last event that was seen. Save the entry event size in the iterator descriptor so that the correct size is used. - Fix several errors with freeing data in the histogram code The histogram code had a lot of leaked or or incorrect accounting when failures happen. Correct them. - Fix histogram regression of .percent and .graph modifiers Up until 6.3 histogram values could have "percent" or "graph" modifiers that changed how they were printed. But a change that added restricting histograms values from being strings, stack traces and other modifiers inadvertently prevented them from using the percent and graph modifiers, which were legal use cases for values. Put back the percent and graph modifiers. - Fix various typos in the comments - Set the trace_clock before initializing a histogram with clock argument The histogram API allows the user to specific which trace clock to use via a "clock=" string. The histogram is set up first before the clock is checked. If the passed in clock is not valid, it exits without fully fixing up the histogram leaving it on the list and a use-after-free can trigger. Update the clock argument first and if it fails then exit gracefully before the histogram trigger is placed on any lists. - Restore :mod: trailer after parsing in ftrace_set_clr_event The function ftrace_set_clr_event() modifies the parse string and needs to put it back to what was passed in. It searches for ":mod:" via a strsep() but fails to put back the first ':' in the string. Add back the ':' in the passed in string. - Take trace_array reference when opening a tracer options file The options files are dynamically created and some tracers add their own options. When a tracer adds their own list of options, the trace_array holding them has an array to hold the list of options for each tracer. This array increases in size via a krealloc(), and the new entry gets a newly allocated array to hold the options of the new tracer being added. The element in each entry of the tracer's option array holds a pointer back to the trace_array, a pointer to the tracer it is associated to, a pointer to the flags of the option. The issue is that these arrays are freed when the trace_array is freed when its instance it represents is removed from the instances directory. There's a race that an open of one of these options files can happen when the instance is being removed. Add a new helper function to be called by the open function of the options file to iterate all existing trace_arrays under a lock and find the one that has the given option element in one of it's tracer arrays. If found, then update the associated trace_array's reference counter to keep it from being freed. If not found, have the open call return -ENODEV. - Disable interrupts when acquiring the lock in rb_wake_up_waiters() The function rb_wake_up_waiters() assumes it will be called in interrupt context and does not disable irqs when taking cpu_buffer->reader_lock, which can be called in hard interrupt context. The issue is in PREEMPT_RT, this function is called in thread context leaving this lock open to a deadlock. Take the lock with interrupts disabled. - Use rcu_assign_pointer() for tmp_ops filter hash The tmp_ops used in update_ftrace_direct_mod() assigns its filter_hash field directly, but that field is annotated as __rcu and sparse complains. Assign it with rcu_assign_pointer() - Fix use-after-free in enable_trigger_private_data_free() The trace_event_call is accessed through the event_trigger_data's trace_event_file pointer to put the trace_event_call on freeing. The issue is that the trace_event_file data may have been freed already causing a use-after-free. Add a field to the event_trigger_data that points directly to the trace_event_call so that it can decrement its reference directly without needing to go through the trace_event_file. - Fix accounting of buffer data remote headers trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount the number of pages is needed for the asked for size as it doesn't take into account the meta data on each page. Add a helper function to do the calculation properly and use that in these functions. - Catch nr_page_va overflow in ring_buffer_desc sizing The number of pages per remote ring buffer is capped by ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to overflow that field would silently allocate a descriptor smaller than what was asked for. - Do not resize the subbuf order if any per_cpu buffer is disabled The mmapping of ring buffers disables resizing the subbuffers, but it is done per-cpu whereas the subbuf size change is done for all the per_cpu buffers under the buffer->mutex. It could change the size of some while the mapping is happening on others. Have the resize of the subbuf order check all the per_cpu buffers under the lock to see if any of them is disabled before starting and causing an inconsistency between buffers that are being mapped. * tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits) ring-buffer: Check resize_disabled before publishing the new subbuf order tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing tracing/remotes: Account for ring buffer page header in size calculation tracing: Don't dereference trace_event_file in deferred trigger free ftrace: Use rcu_assign_pointer() for tmp_ops filter hash ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters() tracing: Take trace_array reference when opening a tracer options file tracing: Fix ring_buffer_read_page_size() kernel-doc tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event() tracing: Fix memory corruption from a "STACKTRACE" histogram key tracing: Fix memory corruption from the histogram stacktrace modifier tracing: Undo the registration when enabling the histogram trigger fails tracing: Take the reference before publishing the named histogram trigger tracing: Set the trace clock before registering the histogram trigger tracing: Fix typo "preceeded" in comment tracing: Fix typo "availabe" in comment tracing: Let histogram values keep the percent and graph modifiers tracing: Keep the entry count when the histogram stats allocation fails tracing: Free histogram the field rejected for a bad modifier tracing: Free histogram the var ref when its initialization fails ... --- lib/asn1_decoder.c | 522 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 522 insertions(+) create mode 100644 lib/asn1_decoder.c (limited to 'lib/asn1_decoder.c') diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c new file mode 100644 index 000000000..5738ae286 --- /dev/null +++ b/lib/asn1_decoder.c @@ -0,0 +1,522 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Decoder for ASN.1 BER/DER/CER encoded bytestream + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include +#include +#include +#include +#include + +static const unsigned char asn1_op_lengths[ASN1_OP__NR] = { + /* OPC TAG JMP ACT */ + [ASN1_OP_MATCH] = 1 + 1, + [ASN1_OP_MATCH_OR_SKIP] = 1 + 1, + [ASN1_OP_MATCH_ACT] = 1 + 1 + 1, + [ASN1_OP_MATCH_ACT_OR_SKIP] = 1 + 1 + 1, + [ASN1_OP_MATCH_JUMP] = 1 + 1 + 1, + [ASN1_OP_MATCH_JUMP_OR_SKIP] = 1 + 1 + 1, + [ASN1_OP_MATCH_ANY] = 1, + [ASN1_OP_MATCH_ANY_OR_SKIP] = 1, + [ASN1_OP_MATCH_ANY_ACT] = 1 + 1, + [ASN1_OP_MATCH_ANY_ACT_OR_SKIP] = 1 + 1, + [ASN1_OP_COND_MATCH_OR_SKIP] = 1 + 1, + [ASN1_OP_COND_MATCH_ACT_OR_SKIP] = 1 + 1 + 1, + [ASN1_OP_COND_MATCH_JUMP_OR_SKIP] = 1 + 1 + 1, + [ASN1_OP_COND_MATCH_ANY] = 1, + [ASN1_OP_COND_MATCH_ANY_OR_SKIP] = 1, + [ASN1_OP_COND_MATCH_ANY_ACT] = 1 + 1, + [ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP] = 1 + 1, + [ASN1_OP_COND_FAIL] = 1, + [ASN1_OP_COMPLETE] = 1, + [ASN1_OP_ACT] = 1 + 1, + [ASN1_OP_MAYBE_ACT] = 1 + 1, + [ASN1_OP_RETURN] = 1, + [ASN1_OP_END_SEQ] = 1, + [ASN1_OP_END_SEQ_OF] = 1 + 1, + [ASN1_OP_END_SET] = 1, + [ASN1_OP_END_SET_OF] = 1 + 1, + [ASN1_OP_END_SEQ_ACT] = 1 + 1, + [ASN1_OP_END_SEQ_OF_ACT] = 1 + 1 + 1, + [ASN1_OP_END_SET_ACT] = 1 + 1, + [ASN1_OP_END_SET_OF_ACT] = 1 + 1 + 1, +}; + +/* + * Find the length of an indefinite length object + * @data: The data buffer + * @datalen: The end of the innermost containing element in the buffer + * @_dp: The data parse cursor (updated before returning) + * @_len: Where to return the size of the element. + * @_errmsg: Where to return a pointer to an error message on error + */ +static int asn1_find_indefinite_length(const unsigned char *data, size_t datalen, + size_t *_dp, size_t *_len, + const char **_errmsg) +{ + unsigned char tag, tmp; + size_t dp = *_dp, len, n; + int indef_level = 1; + +next_tag: + if (unlikely(datalen - dp < 2)) { + if (datalen == dp) + goto missing_eoc; + goto data_overrun_error; + } + + /* Extract a tag from the data */ + tag = data[dp++]; + if (tag == ASN1_EOC) { + /* It appears to be an EOC. */ + if (data[dp++] != 0) + goto invalid_eoc; + if (--indef_level <= 0) { + *_len = dp - *_dp; + *_dp = dp; + return 0; + } + goto next_tag; + } + + if (unlikely((tag & 0x1f) == ASN1_LONG_TAG)) { + do { + if (unlikely(datalen - dp < 2)) + goto data_overrun_error; + tmp = data[dp++]; + } while (tmp & 0x80); + } + + /* Extract the length */ + len = data[dp++]; + if (len <= 0x7f) + goto check_length; + + if (unlikely(len == ASN1_INDEFINITE_LENGTH)) { + /* Indefinite length */ + if (unlikely((tag & ASN1_CONS_BIT) == ASN1_PRIM << 5)) + goto indefinite_len_primitive; + indef_level++; + goto next_tag; + } + + n = len - 0x80; + if (unlikely(n > sizeof(len) - 1)) + goto length_too_long; + if (unlikely(n > datalen - dp)) + goto data_overrun_error; + len = 0; + for (; n > 0; n--) { + len <<= 8; + len |= data[dp++]; + } +check_length: + if (len > datalen - dp) + goto data_overrun_error; + dp += len; + goto next_tag; + +length_too_long: + *_errmsg = "Unsupported length"; + goto error; +indefinite_len_primitive: + *_errmsg = "Indefinite len primitive not permitted"; + goto error; +invalid_eoc: + *_errmsg = "Invalid length EOC"; + goto error; +data_overrun_error: + *_errmsg = "Data overrun error"; + goto error; +missing_eoc: + *_errmsg = "Missing EOC in indefinite len cons"; +error: + *_dp = dp; + return -1; +} + +/** + * asn1_ber_decoder - Decoder BER/DER/CER ASN.1 according to pattern + * @decoder: The decoder definition (produced by asn1_compiler) + * @context: The caller's context (to be passed to the action functions) + * @data: The encoded data + * @datalen: The size of the encoded data + * + * Decode BER/DER/CER encoded ASN.1 data according to a bytecode pattern + * produced by asn1_compiler. Action functions are called on marked tags to + * allow the caller to retrieve significant data. + * + * LIMITATIONS: + * + * To keep down the amount of stack used by this function, the following limits + * have been imposed: + * + * (1) This won't handle datalen > 65535 without increasing the size of the + * cons stack elements and length_too_long checking. + * + * (2) The stack of constructed types is 10 deep. If the depth of non-leaf + * constructed types exceeds this, the decode will fail. + * + * (3) The SET type (not the SET OF type) isn't really supported as tracking + * what members of the set have been seen is a pain. + */ +int asn1_ber_decoder(const struct asn1_decoder *decoder, + void *context, + const unsigned char *data, + size_t datalen) +{ + const unsigned char *machine = decoder->machine; + const asn1_action_t *actions = decoder->actions; + size_t machlen = decoder->machlen; + enum asn1_opcode op; + unsigned char tag = 0, csp = 0, jsp = 0, optag = 0, hdr = 0; + const char *errmsg; + size_t pc = 0, dp = 0, tdp = 0, len = 0; + int ret; + + unsigned char flags = 0; +#define FLAG_INDEFINITE_LENGTH 0x01 +#define FLAG_MATCHED 0x02 +#define FLAG_LAST_MATCHED 0x04 /* Last tag matched */ +#define FLAG_CONS 0x20 /* Corresponds to CONS bit in the opcode tag + * - ie. whether or not we are going to parse + * a compound type. + */ + +#define NR_CONS_STACK 10 + unsigned short cons_dp_stack[NR_CONS_STACK]; + unsigned short cons_datalen_stack[NR_CONS_STACK]; + unsigned char cons_hdrlen_stack[NR_CONS_STACK]; +#define NR_JUMP_STACK 10 + unsigned char jump_stack[NR_JUMP_STACK]; + + if (datalen > 65535) + return -EMSGSIZE; + +next_op: + pr_debug("next_op: pc=\e[32m%zu\e[m/%zu dp=\e[33m%zu\e[m/%zu C=%d J=%d\n", + pc, machlen, dp, datalen, csp, jsp); + if (unlikely(pc >= machlen)) + goto machine_overrun_error; + op = machine[pc]; + if (unlikely(pc + asn1_op_lengths[op] > machlen)) + goto machine_overrun_error; + + /* If this command is meant to match a tag, then do that before + * evaluating the command. + */ + if (op <= ASN1_OP__MATCHES_TAG) { + unsigned char tmp; + + /* Skip conditional matches if possible */ + if ((op & ASN1_OP_MATCH__COND && flags & FLAG_MATCHED) || + (op & ASN1_OP_MATCH__SKIP && dp == datalen)) { + flags &= ~FLAG_LAST_MATCHED; + pc += asn1_op_lengths[op]; + goto next_op; + } + + flags = 0; + hdr = 2; + + /* Extract a tag from the data */ + if (unlikely(datalen - dp < 2)) + goto data_overrun_error; + tag = data[dp++]; + if (unlikely((tag & 0x1f) == ASN1_LONG_TAG)) + goto long_tag_not_supported; + + if (op & ASN1_OP_MATCH__ANY) { + pr_debug("- any %02x\n", tag); + } else { + /* Extract the tag from the machine + * - Either CONS or PRIM are permitted in the data if + * CONS is not set in the op stream, otherwise CONS + * is mandatory. + */ + optag = machine[pc + 1]; + flags |= optag & FLAG_CONS; + + /* Determine whether the tag matched */ + tmp = optag ^ tag; + tmp &= ~(optag & ASN1_CONS_BIT); + pr_debug("- match? %02x %02x %02x\n", tag, optag, tmp); + if (tmp != 0) { + /* All odd-numbered tags are MATCH_OR_SKIP. */ + if (op & ASN1_OP_MATCH__SKIP) { + pc += asn1_op_lengths[op]; + dp--; + goto next_op; + } + goto tag_mismatch; + } + } + flags |= FLAG_MATCHED; + + len = data[dp++]; + if (len > 0x7f) { + if (unlikely(len == ASN1_INDEFINITE_LENGTH)) { + /* Indefinite length */ + if (unlikely(!(tag & ASN1_CONS_BIT))) + goto indefinite_len_primitive; + flags |= FLAG_INDEFINITE_LENGTH; + if (unlikely(2 > datalen - dp)) + goto data_overrun_error; + } else { + int n = len - 0x80; + if (unlikely(n > 2)) + goto length_too_long; + if (unlikely(n > datalen - dp)) + goto data_overrun_error; + hdr += n; + for (len = 0; n > 0; n--) { + len <<= 8; + len |= data[dp++]; + } + if (unlikely(len > datalen - dp)) + goto data_overrun_error; + } + } else { + if (unlikely(len > datalen - dp)) + goto data_overrun_error; + } + + if (flags & FLAG_CONS) { + /* For expected compound forms, we stack the positions + * of the start and end of the data. + */ + if (unlikely(csp >= NR_CONS_STACK)) + goto cons_stack_overflow; + cons_dp_stack[csp] = dp; + cons_hdrlen_stack[csp] = hdr; + if (!(flags & FLAG_INDEFINITE_LENGTH)) { + cons_datalen_stack[csp] = datalen; + datalen = dp + len; + } else { + cons_datalen_stack[csp] = 0; + } + csp++; + } + + pr_debug("- TAG: %02x %zu%s\n", + tag, len, flags & FLAG_CONS ? " CONS" : ""); + tdp = dp; + } + + /* Decide how to handle the operation */ + switch (op) { + case ASN1_OP_MATCH: + case ASN1_OP_MATCH_OR_SKIP: + case ASN1_OP_MATCH_ACT: + case ASN1_OP_MATCH_ACT_OR_SKIP: + case ASN1_OP_MATCH_ANY: + case ASN1_OP_MATCH_ANY_OR_SKIP: + case ASN1_OP_MATCH_ANY_ACT: + case ASN1_OP_MATCH_ANY_ACT_OR_SKIP: + case ASN1_OP_COND_MATCH_OR_SKIP: + case ASN1_OP_COND_MATCH_ACT_OR_SKIP: + case ASN1_OP_COND_MATCH_ANY: + case ASN1_OP_COND_MATCH_ANY_OR_SKIP: + case ASN1_OP_COND_MATCH_ANY_ACT: + case ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP: + + if (!(flags & FLAG_CONS)) { + if (flags & FLAG_INDEFINITE_LENGTH) { + size_t tmp = dp; + + ret = asn1_find_indefinite_length( + data, datalen, &tmp, &len, &errmsg); + if (ret < 0) + goto error; + } + pr_debug("- LEAF: %zu\n", len); + } + + if (op & ASN1_OP_MATCH__ACT) { + unsigned char act; + + if (op & ASN1_OP_MATCH__ANY) + act = machine[pc + 1]; + else + act = machine[pc + 2]; + ret = actions[act](context, hdr, tag, data + dp, len); + if (ret < 0) + return ret; + } + + if (!(flags & FLAG_CONS)) + dp += len; + pc += asn1_op_lengths[op]; + goto next_op; + + case ASN1_OP_MATCH_JUMP: + case ASN1_OP_MATCH_JUMP_OR_SKIP: + case ASN1_OP_COND_MATCH_JUMP_OR_SKIP: + pr_debug("- MATCH_JUMP\n"); + if (unlikely(jsp == NR_JUMP_STACK)) + goto jump_stack_overflow; + jump_stack[jsp++] = pc + asn1_op_lengths[op]; + pc = machine[pc + 2]; + goto next_op; + + case ASN1_OP_COND_FAIL: + if (unlikely(!(flags & FLAG_MATCHED))) + goto tag_mismatch; + pc += asn1_op_lengths[op]; + goto next_op; + + case ASN1_OP_COMPLETE: + if (unlikely(jsp != 0 || csp != 0)) { + pr_err("ASN.1 decoder error: Stacks not empty at completion (%u, %u)\n", + jsp, csp); + return -EBADMSG; + } + return 0; + + case ASN1_OP_END_SET: + case ASN1_OP_END_SET_ACT: + if (unlikely(!(flags & FLAG_MATCHED))) + goto tag_mismatch; + fallthrough; + + case ASN1_OP_END_SEQ: + case ASN1_OP_END_SET_OF: + case ASN1_OP_END_SEQ_OF: + case ASN1_OP_END_SEQ_ACT: + case ASN1_OP_END_SET_OF_ACT: + case ASN1_OP_END_SEQ_OF_ACT: + if (unlikely(csp <= 0)) + goto cons_stack_underflow; + csp--; + tdp = cons_dp_stack[csp]; + hdr = cons_hdrlen_stack[csp]; + len = datalen; + datalen = cons_datalen_stack[csp]; + pr_debug("- end cons t=%zu dp=%zu l=%zu/%zu\n", + tdp, dp, len, datalen); + if (datalen == 0) { + /* Indefinite length - check for the EOC. */ + datalen = len; + if (unlikely(datalen - dp < 2)) + goto data_overrun_error; + if (data[dp++] != 0) { + if (op & ASN1_OP_END__OF) { + dp--; + csp++; + pc = machine[pc + 1]; + pr_debug("- continue\n"); + goto next_op; + } + goto missing_eoc; + } + if (data[dp++] != 0) + goto invalid_eoc; + len = dp - tdp - 2; + } else { + if (dp < len && (op & ASN1_OP_END__OF)) { + datalen = len; + csp++; + pc = machine[pc + 1]; + pr_debug("- continue\n"); + goto next_op; + } + if (dp != len) + goto cons_length_error; + len -= tdp; + pr_debug("- cons len l=%zu d=%zu\n", len, dp - tdp); + } + + if (op & ASN1_OP_END__ACT) { + unsigned char act; + if (op & ASN1_OP_END__OF) + act = machine[pc + 2]; + else + act = machine[pc + 1]; + ret = actions[act](context, hdr, 0, data + tdp, len); + if (ret < 0) + return ret; + } + pc += asn1_op_lengths[op]; + goto next_op; + + case ASN1_OP_MAYBE_ACT: + if (!(flags & FLAG_LAST_MATCHED)) { + pc += asn1_op_lengths[op]; + goto next_op; + } + fallthrough; + + case ASN1_OP_ACT: + ret = actions[machine[pc + 1]](context, hdr, tag, data + tdp, len); + if (ret < 0) + return ret; + pc += asn1_op_lengths[op]; + goto next_op; + + case ASN1_OP_RETURN: + if (unlikely(jsp <= 0)) + goto jump_stack_underflow; + pc = jump_stack[--jsp]; + flags |= FLAG_MATCHED | FLAG_LAST_MATCHED; + goto next_op; + + default: + break; + } + + /* Shouldn't reach here */ + pr_err("ASN.1 decoder error: Found reserved opcode (%u) pc=%zu\n", + op, pc); + return -EBADMSG; + +data_overrun_error: + errmsg = "Data overrun error"; + goto error; +machine_overrun_error: + errmsg = "Machine overrun error"; + goto error; +jump_stack_underflow: + errmsg = "Jump stack underflow"; + goto error; +jump_stack_overflow: + errmsg = "Jump stack overflow"; + goto error; +cons_stack_underflow: + errmsg = "Cons stack underflow"; + goto error; +cons_stack_overflow: + errmsg = "Cons stack overflow"; + goto error; +cons_length_error: + errmsg = "Cons length error"; + goto error; +missing_eoc: + errmsg = "Missing EOC in indefinite len cons"; + goto error; +invalid_eoc: + errmsg = "Invalid length EOC"; + goto error; +length_too_long: + errmsg = "Unsupported length"; + goto error; +indefinite_len_primitive: + errmsg = "Indefinite len primitive not permitted"; + goto error; +tag_mismatch: + errmsg = "Unexpected tag"; + goto error; +long_tag_not_supported: + errmsg = "Long tag not supported"; +error: + pr_debug("\nASN1: %s [m=%zu d=%zu ot=%02x t=%02x l=%zu]\n", + errmsg, pc, dp, optag, tag, len); + return -EBADMSG; +} +EXPORT_SYMBOL_GPL(asn1_ber_decoder); + +MODULE_DESCRIPTION("Decoder for ASN.1 BER/DER/CER encoded bytestream"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1