Phil Sutter <phil@xxxxxx> wrote:
> On Thu, Sep 30, 2021 at 11:53:32AM +0530, Senthil Kumar Balasubramanian wrote:
> > However, dumping the data that goes to the kernel, we see a huge
> > difference between MIPS and ARM..
> >
> > in ARM platform
> > w_l->w:
> > 0000 6e 66 6c 6f 67 00 ff b6 00 00 00 00 00 00 00 00 nflog...........
> > 0010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > 0020 50 00 00 00 00 00 00 00 01 00 01 00 00 00 00 00 P...............
> > 0030 45 4e 54 52 59 31 00 00 00 00 00 00 00 00 00 00 ENTRY1..........
> > 0040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > 0050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > 0060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > 0070 00 00 00 00
> >
> > in tplink a6 (MIPS platform)
> >
> > w_l->w:
> > 0000 6e 66 6c 6f 67 00 b2 e0 69 6d 69 74 20 65 78 63 nflog...imit exc
> > 0010 65 65 64 65 64 00 56 69 72 74 75 61 6c 20 74 69 eeded.Virtual ti
> > 0020 00 00 00 50 65 78 70 69 00 01 00 01 50 72 6f 66 ...Pexpi....Prof
> > 0030 45 4e 54 52 59 31 00 69 6d 65 72 20 65 78 70 69 ENTRY1.imer expi
> > 0040 72 65 64 00 57 69 6e 64 6f 77 20 63 68 61 6e 67 red.Window chang
> > 0050 65 64 00 49 2f 4f 20 70 6f 73 73 69 62 6c 65 00 ed.I/O possible.
> > 0060 50 6f 77 65 72 20 66 61 69 6c 75 72 65 00 42 61 Power failure.Ba
> > 0070 64 20 73 79
> > d sy
> >
> > Can you please let me know what's going wrong with this?
>
> Looks like the data structure contains garbage. Looking at ebtables
> code, that seems likely as extension data structures are allocated using
> malloc() and never set zero. init() function in ebt_nflog.c only
> initializes prefix, group and threshold fields (which seem to be set
> correctly in your MIPS dump).
Yes, probably pure luck (libc differences and the like).
Senthil, can you try this patch (compile tested only)?
diff --git a/libebtc.c b/libebtc.c
--- a/libebtc.c
+++ b/libebtc.c
@@ -41,6 +41,18 @@
static void decrease_chain_jumps(struct ebt_u_replace *replace);
static int iterate_entries(struct ebt_u_replace *replace, int type);
+static void *xzalloc(size_t s)
+{
+ void *p = malloc(s);
+
+ if (!p)
+ ebt_print_memory();
+
+ memset(p, 0, s);
+
+ return p;
+}
+
/* The standard names */
const char *ebt_hooknames[NF_BR_NUMHOOKS] =
{
@@ -266,9 +278,7 @@ void ebt_reinit_extensions()
for (m = ebt_matches; m; m = m->next) {
if (m->used) {
size = EBT_ALIGN(m->size) + sizeof(struct ebt_entry_match);
- m->m = (struct ebt_entry_match *)malloc(size);
- if (!m->m)
- ebt_print_memory();
+ m->m = xzalloc(size);
strcpy(m->m->u.name, m->name);
m->m->u.revision = m->revision;
m->m->match_size = EBT_ALIGN(m->size);
@@ -280,9 +290,7 @@ void ebt_reinit_extensions()
for (w = ebt_watchers; w; w = w->next) {
if (w->used) {
size = EBT_ALIGN(w->size) + sizeof(struct ebt_entry_watcher);
- w->w = (struct ebt_entry_watcher *)malloc(size);
- if (!w->w)
- ebt_print_memory();
+ w->w = xzalloc(size);
strcpy(w->w->u.name, w->name);
w->w->watcher_size = EBT_ALIGN(w->size);
w->used = 0;
@@ -293,9 +301,7 @@ void ebt_reinit_extensions()
for (t = ebt_targets; t; t = t->next) {
if (t->used) {
size = EBT_ALIGN(t->size) + sizeof(struct ebt_entry_target);
- t->t = (struct ebt_entry_target *)malloc(size);
- if (!t->t)
- ebt_print_memory();
+ t->t = xzalloc(size);
strcpy(t->t->u.name, t->name);
t->t->target_size = EBT_ALIGN(t->size);
t->used = 0;
@@ -645,9 +651,7 @@ void ebt_add_rule(struct ebt_u_replace *replace, struct ebt_u_entry *new_entry,
new_entry->prev = u_e->prev;
u_e->prev->next = new_entry;
u_e->prev = new_entry;
- new_cc = (struct ebt_cntchanges *)malloc(sizeof(struct ebt_cntchanges));
- if (!new_cc)
- ebt_print_memory();
+ new_cc = xzalloc(sizeof(struct ebt_cntchanges));
new_cc->type = CNT_ADD;
new_cc->change = 0;
if (new_entry->next == entries->entries) {
@@ -861,18 +865,14 @@ void ebt_new_chain(struct ebt_u_replace *replace, const char *name, int policy)
if (replace->num_chains == replace->max_chains)
ebt_double_chains(replace);
- new = (struct ebt_u_entries *)malloc(sizeof(struct ebt_u_entries));
- if (!new)
- ebt_print_memory();
+ new = xzalloc(sizeof(struct ebt_u_entries));
replace->chains[replace->num_chains++] = new;
new->nentries = 0;
new->policy = policy;
new->counter_offset = replace->nentries;
new->hook_mask = 0;
strcpy(new->name, name);
- new->entries = (struct ebt_u_entry *)malloc(sizeof(struct ebt_u_entry));
- if (!new->entries)
- ebt_print_memory();
+ new->entries = xzalloc(sizeof(struct ebt_u_entry));
new->entries->next = new->entries->prev = new->entries;
new->kernel_start = NULL;
}
@@ -1041,7 +1041,7 @@ void ebt_check_for_loops(struct ebt_u_replace *replace)
}
if (replace->num_chains == NF_BR_NUMHOOKS)
return;
- stack = (struct ebt_u_stack *)malloc((replace->num_chains - NF_BR_NUMHOOKS) * sizeof(struct ebt_u_stack));
+ stack = calloc((replace->num_chains - NF_BR_NUMHOOKS), sizeof(struct ebt_u_stack));
if (!stack)
ebt_print_memory();
@@ -1111,10 +1111,7 @@ void ebt_add_match(struct ebt_u_entry *new_entry, struct ebt_u_match *m)
struct ebt_u_match_list **m_list, *new;
for (m_list = &new_entry->m_list; *m_list; m_list = &(*m_list)->next);
- new = (struct ebt_u_match_list *)
- malloc(sizeof(struct ebt_u_match_list));
- if (!new)
- ebt_print_memory();
+ new = xzalloc(sizeof(struct ebt_u_match_list));
*m_list = new;
new->next = NULL;
new->m = (struct ebt_entry_match *)m;
@@ -1126,10 +1123,7 @@ void ebt_add_watcher(struct ebt_u_entry *new_entry, struct ebt_u_watcher *w)
struct ebt_u_watcher_list *new;
for (w_list = &new_entry->w_list; *w_list; w_list = &(*w_list)->next);
- new = (struct ebt_u_watcher_list *)
- malloc(sizeof(struct ebt_u_watcher_list));
- if (!new)
- ebt_print_memory();
+ new = xzalloc(sizeof(struct ebt_u_watcher_list));
*w_list = new;
new->next = NULL;
new->w = (struct ebt_entry_watcher *)w;
@@ -1206,9 +1200,7 @@ void ebt_register_match(struct ebt_u_match *m)
int size = EBT_ALIGN(m->size) + sizeof(struct ebt_entry_match);
struct ebt_u_match **i;
- m->m = (struct ebt_entry_match *)malloc(size);
- if (!m->m)
- ebt_print_memory();
+ m->m = xzalloc(size);
strcpy(m->m->u.name, m->name);
m->m->u.revision = m->revision;
m->m->match_size = EBT_ALIGN(m->size);
@@ -1224,9 +1216,7 @@ void ebt_register_watcher(struct ebt_u_watcher *w)
int size = EBT_ALIGN(w->size) + sizeof(struct ebt_entry_watcher);
struct ebt_u_watcher **i;
- w->w = (struct ebt_entry_watcher *)malloc(size);
- if (!w->w)
- ebt_print_memory();
+ w->w = xzalloc(size);
strcpy(w->w->u.name, w->name);
w->w->watcher_size = EBT_ALIGN(w->size);
w->init(w->w);
@@ -1241,9 +1231,7 @@ void ebt_register_target(struct ebt_u_target *t)
int size = EBT_ALIGN(t->size) + sizeof(struct ebt_entry_target);
struct ebt_u_target **i;
- t->t = (struct ebt_entry_target *)malloc(size);
- if (!t->t)
- ebt_print_memory();
+ t->t = xzalloc(size);
strcpy(t->t->u.name, t->name);
t->t->target_size = EBT_ALIGN(t->size);
t->init(t->t);
