5.4-stable review patch. If anyone has any objections, please let me know.
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From: Yuan Chen chenyuan@kylinos.cn
[ Upstream commit 99fe8af069a9fa5b09140518b1364e35713a642e ]
In function dump_xx_nlmsg(), when realloc() fails to allocate memory, the original pointer to the buffer is overwritten with NULL. This causes a memory leak because the previously allocated buffer becomes unreachable without being freed.
Fixes: 7900efc19214 ("tools/bpf: bpftool: improve output format for bpftool net") Signed-off-by: Yuan Chen chenyuan@kylinos.cn Reviewed-by: Quentin Monnet qmo@kernel.org Link: https://lore.kernel.org/r/20250620012133.14819-1-chenyuan_fl@163.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/bpf/bpftool/net.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c index c6787a1daa48..c2953b2bf130 100644 --- a/tools/bpf/bpftool/net.c +++ b/tools/bpf/bpftool/net.c @@ -87,17 +87,18 @@ static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb) { struct bpf_netdev_t *netinfo = cookie; struct ifinfomsg *ifinfo = msg; + struct ip_devname_ifindex *tmp;
if (netinfo->filter_idx > 0 && netinfo->filter_idx != ifinfo->ifi_index) return 0;
if (netinfo->used_len == netinfo->array_len) { - netinfo->devices = realloc(netinfo->devices, - (netinfo->array_len + 16) * - sizeof(struct ip_devname_ifindex)); - if (!netinfo->devices) + tmp = realloc(netinfo->devices, + (netinfo->array_len + 16) * sizeof(struct ip_devname_ifindex)); + if (!tmp) return -ENOMEM;
+ netinfo->devices = tmp; netinfo->array_len += 16; } netinfo->devices[netinfo->used_len].ifindex = ifinfo->ifi_index; @@ -116,6 +117,7 @@ static int dump_class_qdisc_nlmsg(void *cookie, void *msg, struct nlattr **tb) { struct bpf_tcinfo_t *tcinfo = cookie; struct tcmsg *info = msg; + struct tc_kind_handle *tmp;
if (tcinfo->is_qdisc) { /* skip clsact qdisc */ @@ -127,11 +129,12 @@ static int dump_class_qdisc_nlmsg(void *cookie, void *msg, struct nlattr **tb) }
if (tcinfo->used_len == tcinfo->array_len) { - tcinfo->handle_array = realloc(tcinfo->handle_array, + tmp = realloc(tcinfo->handle_array, (tcinfo->array_len + 16) * sizeof(struct tc_kind_handle)); - if (!tcinfo->handle_array) + if (!tmp) return -ENOMEM;
+ tcinfo->handle_array = tmp; tcinfo->array_len += 16; } tcinfo->handle_array[tcinfo->used_len].handle = info->tcm_handle;