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Skeleton headers for host isolation #130

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Skeleton headers for host isolation #130

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90d5193
Switch TcLoader to use skeleton header
stanek-michal Aug 24, 2022
a985175
Be explicit about the dry run option
stanek-michal Aug 25, 2022
04ac43d
use proper bool
stanek-michal Aug 25, 2022
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2 changes: 1 addition & 1 deletion non-GPL/Events/EventsTrace/EventsTrace.c
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Original file line number Diff line number Diff line change
Expand Up @@ -666,7 +666,7 @@ int main(int argc, char **argv)
if (g_features_autodetect)
ebpf_detect_system_features(&opts.features);

err = ebpf_event_ctx__new(&ctx, event_ctx_callback, opts);
err = ebpf_event_ctx__new(&ctx, event_ctx_callback, opts, /* dry_run= */ false);

if (err < 0) {
fprintf(stderr, "Could not create event context: %d %s\n", err, strerror(-err));
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12 changes: 10 additions & 2 deletions non-GPL/Events/Lib/EbpfEvents.c
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Expand Up @@ -405,7 +405,8 @@ int ebpf_set_verbose_logging()

int ebpf_event_ctx__new(struct ebpf_event_ctx **ctx,
ebpf_event_handler_fn cb,
struct ebpf_event_ctx_opts opts)
struct ebpf_event_ctx_opts opts,
bool dry_run)
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This addition doesn't really change functionality but I wanted to make this option more explicit in the code to prevent bugs or relying on a certain behavior in the function. We did in fact had bugs like this in this function before. The Host Isolation version of this also has a dryRun parameter.

{
struct EventProbe_bpf *probe = NULL;
struct btf *btf = NULL;
Expand Down Expand Up @@ -469,8 +470,15 @@ int ebpf_event_ctx__new(struct ebpf_event_ctx **ctx,
if (err != 0)
goto out_destroy_probe;

if (!ctx)
if (dry_run) {
err = 0;
goto out_destroy_probe;
}

if (!ctx) {
err = -ENOENT;
goto out_destroy_probe;
}

*ctx = calloc(1, sizeof(struct ebpf_event_ctx));
if (*ctx == NULL) {
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9 changes: 5 additions & 4 deletions non-GPL/Events/Lib/EbpfEvents.h
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Expand Up @@ -36,16 +36,17 @@ int ebpf_detect_system_features(uint64_t *features);

/* Allocates a new context based on requested events and capabilities.
*
* If ctx is NULL, the function returns right after loading and attaching the
* libbpf skeleton.
* If dry_run is true, the function only tests load and attach to
* verify host compatibility.
*
* Returns a positive int that represents an fd, which can be used with epoll
* on success. Returns an error on failure. If ctx is NULL,
* on success. Returns an error on failure. If dry_run is true,
* returns 0 on success or less than 0 on failure.
*/
int ebpf_event_ctx__new(struct ebpf_event_ctx **ctx,
ebpf_event_handler_fn cb,
struct ebpf_event_ctx_opts opts);
struct ebpf_event_ctx_opts opts,
bool dry_run);

/* Consumes as many events as possible from the event context and returns the
* number consumed.
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19 changes: 16 additions & 3 deletions non-GPL/HostIsolation/Lib/TcLoader.c
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Expand Up @@ -473,22 +473,35 @@ int netlink_filter_add_begin(struct netlink_ctx *ctx, const char *ifname)
int netlink_filter_add_end(int fd, struct netlink_ctx *ctx, const char *ebpf_obj_filename)
{
struct nlmsghdr *nl = NULL;
struct bpf_prog_info info = {};
unsigned int info_len = sizeof(info);
char buf[128];
int rv = -1;
int len = 0;

if (!ctx || !ebpf_obj_filename) {
if (!ctx) {
ebpf_log("netlink_filter_add_end error: NULL parameter\n");
rv = -1;
goto out;
}

rv = bpf_obj_get_info_by_fd(fd, &info, &info_len);
if (rv < 0) {
ebpf_log("netlink_filter_add_end error: failed to get info by fd\n");
goto out;
}

nl = &ctx->msg.n;
memset(buf, 0, sizeof(buf));

len = snprintf(buf, sizeof(buf), "%s:[.text]", ebpf_obj_filename);
if (ebpf_obj_filename) {
len = snprintf(buf, sizeof(buf), "%s:[.text]", ebpf_obj_filename);
} else {
len = snprintf(buf, sizeof(buf), "%s:[%u]", info.name, info.id);
}

if (len < 0 || len >= sizeof(buf)) {
ebpf_log("netlink_filter_add_end error: filename too long\n");
ebpf_log("netlink_filter_add_end error: name too long\n");
rv = -1;
goto out;
}
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2 changes: 1 addition & 1 deletion non-GPL/HostIsolation/Lib/TcLoader.h
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Original file line number Diff line number Diff line change
Expand Up @@ -77,7 +77,7 @@ int netlink_filter_add_begin(struct netlink_ctx *ctx, const char *ifname);
* @param[in] fd eBPF program file descriptor
* @param[in] ctx Context containing netlink state (from previous add_begin()
* call) - passed by caller
* @param[in] ebpf_obj_filename eBPF object filename
* @param[in] ebpf_obj_filename eBPF object filename (NULL if using skeleton header)
* @return Error value (0 for success)
*/
int netlink_filter_add_end(int fd, struct netlink_ctx *ctx, const char *ebpf_obj_filename);
Expand Down