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Commit 28d36e37 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

[FIB]: Avoid using static variables without proper locking 



fib_trie_seq_show() uses two helper functions, rtn_scope() and
rtn_type() that can write to static storage without locking.

Just pass to them a temporary buffer to avoid potential corruption
(probably not triggerable but still...)

Signed-off-by: default avatarEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 39a6d063

net/ipv4/fib_trie.c

+12 −10
Original line number Diff line number Diff line
@@ -2284,10 +2284,8 @@ static void seq_indent(struct seq_file *seq, int n) 
	while (n-- > 0) seq_puts(seq, "   ");

}



static inline const char *rtn_scope(enum rt_scope_t s)

static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)

{

	static char buf[32];



	switch (s) {

	case RT_SCOPE_UNIVERSE: return "universe";

	case RT_SCOPE_SITE:	return "site";
@@ -2295,7 +2293,7 @@ static inline const char *rtn_scope(enum rt_scope_t s) 
	case RT_SCOPE_HOST:	return "host";

	case RT_SCOPE_NOWHERE:	return "nowhere";

	default:

		snprintf(buf, sizeof(buf), "scope=%d", s);

		snprintf(buf, len, "scope=%d", s);

		return buf;

	}

}
@@ -2315,13 +2313,11 @@ static const char *rtn_type_names[__RTN_MAX] = { 
	[RTN_XRESOLVE] = "XRESOLVE",

};



static inline const char *rtn_type(unsigned t)

static inline const char *rtn_type(char *buf, size_t len, unsigned t)

{

	static char buf[32];



	if (t < __RTN_MAX && rtn_type_names[t])

		return rtn_type_names[t];

	snprintf(buf, sizeof(buf), "type %u", t);

	snprintf(buf, len, "type %u", t);

	return buf;

}
@@ -2359,13 +2355,19 @@ static int fib_trie_seq_show(struct seq_file *seq, void *v) 
		seq_printf(seq, "  |-- %d.%d.%d.%d\n", NIPQUAD(val));

		for (i = 32; i >= 0; i--) {

			struct leaf_info *li = find_leaf_info(l, i);



			if (li) {

				struct fib_alias *fa;



				list_for_each_entry_rcu(fa, &li->falh, fa_list) {

					char buf1[32], buf2[32];



					seq_indent(seq, iter->depth+1);

					seq_printf(seq, "  /%d %s %s", i,

						   rtn_scope(fa->fa_scope),

						   rtn_type(fa->fa_type));

						   rtn_scope(buf1, sizeof(buf1),

							     fa->fa_scope),

						   rtn_type(buf2, sizeof(buf2),

							     fa->fa_type));

					if (fa->fa_tos)

						seq_printf(seq, "tos =%d\n",

							   fa->fa_tos);