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perf trace augmented_raw_syscalls: Add more checks to pass the verifier

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Add some more checks to pass the verifier in more kernels.

Signed-off-by: Howard Chu <howardchu95@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241011021403.4089793-3-howardchu95@gmail.com
[ Reduced the patch removing things that can be done later ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Howard Chu 2024-10-10 19:14:02 -07:00 committed by Arnaldo Carvalho de Melo
parent ecabac70ff
commit 395d38419f
1 changed files with 18 additions and 2 deletions
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20
tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c
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@ -288,6 +288,10 @@ int sys_enter_rename(struct syscall_enter_args *args)
augmented_args->arg.size = PERF_ALIGN(oldpath_len + 1, sizeof(u64)); augmented_args->arg.size = PERF_ALIGN(oldpath_len + 1, sizeof(u64));
len += augmented_args->arg.size; len += augmented_args->arg.size;
/* Every read from userspace is limited to value size */
if (augmented_args->arg.size > sizeof(augmented_args->arg.value))
return 1; /* Failure: don't filter */
struct augmented_arg *arg2 = (void *)&augmented_args->arg.value + augmented_args->arg.size; struct augmented_arg *arg2 = (void *)&augmented_args->arg.value + augmented_args->arg.size;
newpath_len = augmented_arg__read_str(arg2, newpath_arg, sizeof(augmented_args->arg.value)); newpath_len = augmented_arg__read_str(arg2, newpath_arg, sizeof(augmented_args->arg.value));
@ -315,6 +319,10 @@ int sys_enter_renameat2(struct syscall_enter_args *args)
augmented_args->arg.size = PERF_ALIGN(oldpath_len + 1, sizeof(u64)); augmented_args->arg.size = PERF_ALIGN(oldpath_len + 1, sizeof(u64));
len += augmented_args->arg.size; len += augmented_args->arg.size;
/* Every read from userspace is limited to value size */
if (augmented_args->arg.size > sizeof(augmented_args->arg.value))
return 1; /* Failure: don't filter */
struct augmented_arg *arg2 = (void *)&augmented_args->arg.value + augmented_args->arg.size; struct augmented_arg *arg2 = (void *)&augmented_args->arg.value + augmented_args->arg.size;
newpath_len = augmented_arg__read_str(arg2, newpath_arg, sizeof(augmented_args->arg.value)); newpath_len = augmented_arg__read_str(arg2, newpath_arg, sizeof(augmented_args->arg.value));
@ -423,8 +431,9 @@ static bool pid_filter__has(struct pids_filtered *pids, pid_t pid)
static int augment_sys_enter(void *ctx, struct syscall_enter_args *args) static int augment_sys_enter(void *ctx, struct syscall_enter_args *args)
{ {
bool augmented, do_output = false; bool augmented, do_output = false;
int zero = 0, size, aug_size, index, output = 0, int zero = 0, size, aug_size, index,
value_size = sizeof(struct augmented_arg) - offsetof(struct augmented_arg, value); value_size = sizeof(struct augmented_arg) - offsetof(struct augmented_arg, value);
u64 output = 0; /* has to be u64, otherwise it won't pass the verifier */
unsigned int nr, *beauty_map; unsigned int nr, *beauty_map;
struct beauty_payload_enter *payload; struct beauty_payload_enter *payload;
void *arg, *payload_offset; void *arg, *payload_offset;
@ -490,10 +499,17 @@ static int augment_sys_enter(void *ctx, struct syscall_enter_args *args)
} }
} }
/* Augmented data size is limited to sizeof(augmented_arg->unnamed union with value field) */
if (aug_size > value_size)
aug_size = value_size;
/* write data to payload */ /* write data to payload */
if (augmented) { if (augmented) {
int written = offsetof(struct augmented_arg, value) + aug_size; int written = offsetof(struct augmented_arg, value) + aug_size;
if (written < 0 || written > sizeof(struct augmented_arg))
return 1;
((struct augmented_arg *)payload_offset)->size = aug_size; ((struct augmented_arg *)payload_offset)->size = aug_size;
output += written; output += written;
payload_offset += written; payload_offset += written;
@ -501,7 +517,7 @@ static int augment_sys_enter(void *ctx, struct syscall_enter_args *args)
} }
} }
if (!do_output) if (!do_output || (sizeof(struct syscall_enter_args) + output) > sizeof(struct beauty_payload_enter))
return 1; return 1;
return augmented__beauty_output(ctx, payload, sizeof(struct syscall_enter_args) + output); return augmented__beauty_output(ctx, payload, sizeof(struct syscall_enter_args) + output);