| Message ID | 1682696089-27937-4-git-send-email-alan.maguire@oracle.com |
|---|---|
| State | New |
| Headers | show |
| Series | tracing: additional filter predicates | expand |
BTW, the subjects for the tracing subsystem should always start with a capital letter. "tracing: Support IPv6 filter predicates" But that's not why I'm replying here. On Fri, 28 Apr 2023 16:34:46 +0100 Alan Maguire <alan.maguire@oracle.com> wrote: > Support '==' and '!=' predicates for IPv6 addresses; > for example > > cd /sys/kernel/debug/tracing/events/tcp/tcp_receive_reset > echo "saddr_v6 == ::1" > filter > > or equivalently > > echo "saddr_v6 == 0:0:0:0:0:0:0:1" > filter > > Signed-off-by: Alan Maguire <alan.maguire@oracle.com> > --- > kernel/trace/trace_events_filter.c | 73 ++++++++++++++++++++++++++++++ > 1 file changed, 73 insertions(+) > > diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c > index d8e08d3c3594..e2521574f3c4 100644 > --- a/kernel/trace/trace_events_filter.c > +++ b/kernel/trace/trace_events_filter.c > @@ -1665,6 +1665,79 @@ static int parse_pred(const char *str, void *data, > if (pred->op == OP_NE) > pred->not = 1; > > + } else if (field->size == 16 && > + (str[i] == ':' || > + (isalnum(str[i]) && tolower(str[i + 1]) != 'x'))) { > + u8 j, gap_size, gap = 0, gap_count = 0, index = 0; > + u16 tmp_v6addr[8] = {}; > + u16 v6addr[8] = {}; > + > + /* For IPv6 addresses, only '==' or '!=' are supported. */ > + if (pred->op != OP_EQ && pred->op != OP_NE) { > + parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i); > + goto err_free; > + } > + /* Store the u16s in the address string consecutively in > + * tmp_v6addr while tracking the presence of a "::" (if any) > + * in the IPv6 address string; we will use its location > + * to determine how many u16s it represents (the gap_size > + * below). Only one "::" is allowed in an IPv6 address > + * string. > + */ > + while (isalnum(str[i]) || str[i] == ':') { > + switch (str[i]) { > + case ':': > + i++; > + /* mark "::" index by setting gap */ > + if (str[i] == ':') { > + gap = index; > + gap_count++; > + i++; > + } > + if (gap_count > 1) { > + parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, > + pos + s); > + goto err_free; > + } > + break; > + default: > + if (sscanf(&str[i], "%hx", &tmp_v6addr[index]) != 1) { > + parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, > + pos + s); > + goto err_free; > + } > + index++; > + while (isalnum(str[i])) > + i++; > + break; > + } > + } There appears to be no limit to the above loop. I panic'd my machine with: # echo 'saddr_v6 == 0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef' > /sys/kernel/tracing/events/sock/inet_sk_error_report/filter -- Steve > + /* The gap_size here represents the number of u16s the "::" > + * represents; for ::1 the gap size is 7, for feed::face > + * it is 6, etc. > + */ > + gap_size = 8 - index; > + index = 0; > + for (j = 0; j < 8; ) { > + if (gap_size > 0 && j == gap) { > + j += gap_size; > + } else { > +#ifdef __BIG_ENDIAN > + v6addr[j++] = tmp_v6addr[index]; > +#else > + v6addr[j++] = ((tmp_v6addr[index] & 0xff) << 8) + > + ((tmp_v6addr[index] & 0xff00) >> 8); > +#endif > + index++; > + } > + } > + pred_val = kzalloc(field->size, GFP_KERNEL); > + memcpy(pred_val, v6addr, field->size); > + pred->val = (u64)pred_val; > + pred->fn_num = FILTER_PRED_FN_MEMCMP; > + if (pred->op == OP_NE) > + pred->not = 1; > + > } else if (str[i] == '0' && tolower(str[i + 1]) == 'x' && > field->size > 8) { > /* For sizes > 8 bytes, we store hex bytes for comparison;
On Fri, 9 Jun 2023 17:12:27 -0400 Steven Rostedt <rostedt@goodmis.org> wrote: > > + while (isalnum(str[i]) || str[i] == ':') { > > + switch (str[i]) { > > + case ':': > > + i++; > > + /* mark "::" index by setting gap */ > > + if (str[i] == ':') { > > + gap = index; > > + gap_count++; > > + i++; > > + } > > + if (gap_count > 1) { > > + parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, > > + pos + s); > > + goto err_free; > > + } > > + break; > > + default: > > + if (sscanf(&str[i], "%hx", &tmp_v6addr[index]) != 1) { > > + parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, > > + pos + s); > > + goto err_free; > > + } > > + index++; > > + while (isalnum(str[i])) > > + i++; > > + break; There should also be a lot more checks here where the input coming in is correct. It also accepted: "123456789abcdef0" as "def0", where I expected it to fail. -- Steve > > + } > > + } > > There appears to be no limit to the above loop. I panic'd my machine with: > > # echo 'saddr_v6 == 0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef:0123:4567:89ab:cdef' > /sys/kernel/tracing/events/sock/inet_sk_error_report/filter > > -- Steve > > > + /* The gap_size here represents the number of u16s the "::" > > + * represents; for ::1 the gap size is 7, for feed::face > > + * it is 6, etc. > > + */ > > + gap_size = 8 - index; > > + index = 0; > > + for (j = 0; j < 8; ) { > > + if (gap_size > 0 && j == gap) { > > + j += gap_size; > > + } else { > > +#ifdef __BIG_ENDIAN > > + v6addr[j++] = tmp_v6addr[index]; > > +#else > > + v6addr[j++] = ((tmp_v6addr[index] & 0xff) << 8) + > > + ((tmp_v6addr[index] & 0xff00) >> 8); > > +#endif > > + index++; > > + } > > + } > > + pred_val = kzalloc(field->size, GFP_KERNEL); > > + memcpy(pred_val, v6addr, field->size); > > + pred->val = (u64)pred_val; > > + pred->fn_num = FILTER_PRED_FN_MEMCMP; > > + if (pred->op == OP_NE) > > + pred->not = 1; > > + > > } else if (str[i] == '0' && tolower(str[i + 1]) == 'x' && > > field->size > 8) { > > /* For sizes > 8 bytes, we store hex bytes for comparison;
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index d8e08d3c3594..e2521574f3c4 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1665,6 +1665,79 @@ static int parse_pred(const char *str, void *data, if (pred->op == OP_NE) pred->not = 1; + } else if (field->size == 16 && + (str[i] == ':' || + (isalnum(str[i]) && tolower(str[i + 1]) != 'x'))) { + u8 j, gap_size, gap = 0, gap_count = 0, index = 0; + u16 tmp_v6addr[8] = {}; + u16 v6addr[8] = {}; + + /* For IPv6 addresses, only '==' or '!=' are supported. */ + if (pred->op != OP_EQ && pred->op != OP_NE) { + parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i); + goto err_free; + } + /* Store the u16s in the address string consecutively in + * tmp_v6addr while tracking the presence of a "::" (if any) + * in the IPv6 address string; we will use its location + * to determine how many u16s it represents (the gap_size + * below). Only one "::" is allowed in an IPv6 address + * string. + */ + while (isalnum(str[i]) || str[i] == ':') { + switch (str[i]) { + case ':': + i++; + /* mark "::" index by setting gap */ + if (str[i] == ':') { + gap = index; + gap_count++; + i++; + } + if (gap_count > 1) { + parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, + pos + s); + goto err_free; + } + break; + default: + if (sscanf(&str[i], "%hx", &tmp_v6addr[index]) != 1) { + parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, + pos + s); + goto err_free; + } + index++; + while (isalnum(str[i])) + i++; + break; + } + } + /* The gap_size here represents the number of u16s the "::" + * represents; for ::1 the gap size is 7, for feed::face + * it is 6, etc. + */ + gap_size = 8 - index; + index = 0; + for (j = 0; j < 8; ) { + if (gap_size > 0 && j == gap) { + j += gap_size; + } else { +#ifdef __BIG_ENDIAN + v6addr[j++] = tmp_v6addr[index]; +#else + v6addr[j++] = ((tmp_v6addr[index] & 0xff) << 8) + + ((tmp_v6addr[index] & 0xff00) >> 8); +#endif + index++; + } + } + pred_val = kzalloc(field->size, GFP_KERNEL); + memcpy(pred_val, v6addr, field->size); + pred->val = (u64)pred_val; + pred->fn_num = FILTER_PRED_FN_MEMCMP; + if (pred->op == OP_NE) + pred->not = 1; + } else if (str[i] == '0' && tolower(str[i + 1]) == 'x' && field->size > 8) { /* For sizes > 8 bytes, we store hex bytes for comparison;
Support '==' and '!=' predicates for IPv6 addresses; for example cd /sys/kernel/debug/tracing/events/tcp/tcp_receive_reset echo "saddr_v6 == ::1" > filter or equivalently echo "saddr_v6 == 0:0:0:0:0:0:0:1" > filter Signed-off-by: Alan Maguire <alan.maguire@oracle.com> --- kernel/trace/trace_events_filter.c | 73 ++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+)