The option 255 (end of options) do not need the length byte, this change
remove that allowing to have one extra byte at other dynamic options.
Signed-off-by: Enrique Llorente <ellorent(a)redhat.com>
---
dhcp.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/dhcp.c b/dhcp.c
index 401cb5b..3aef13f 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -127,7 +127,7 @@ struct msg {
uint8_t sname[64];
uint8_t file[128];
uint32_t magic;
- uint8_t o[OPT_MAX + 2 /* End option and its length */ ];
+ uint8_t o[OPT_MAX + 1 /* End option */ ];
} __attribute__((__packed__));
/**
@@ -194,7 +194,6 @@ static int fill(struct msg *m)
}
m->o[offset++] = 255;
- m->o[offset++] = 0;
if (offset < OPT_MIN) {
memset(&m->o[offset], 0, OPT_MIN - offset);
--
2.47.0
On Tue, Feb 11, 2025 at 12:14:34PM +0100, Enrique Llorente wrote:The option 255 (end of options) do not need the length byte, this change remove that allowing to have one extra byte at other dynamic options. Signed-off-by: Enrique Llorente <ellorent(a)redhat.com>Thanks, change is good. However, could you also update the comment on OPT_MAX's definition that appears to have the same error in it.--- dhcp.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/dhcp.c b/dhcp.c index 401cb5b..3aef13f 100644 --- a/dhcp.c +++ b/dhcp.c @@ -127,7 +127,7 @@ struct msg { uint8_t sname[64]; uint8_t file[128]; uint32_t magic; - uint8_t o[OPT_MAX + 2 /* End option and its length */ ]; + uint8_t o[OPT_MAX + 1 /* End option */ ]; } __attribute__((__packed__)); /** @@ -194,7 +194,6 @@ static int fill(struct msg *m) } m->o[offset++] = 255; - m->o[offset++] = 0; if (offset < OPT_MIN) { memset(&m->o[offset], 0, OPT_MIN - offset);-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson
On Wed, 12 Feb 2025 12:14:32 +1100 David Gibson <david(a)gibson.dropbear.id.au> wrote:On Tue, Feb 11, 2025 at 12:14:34PM +0100, Enrique Llorente wrote:I was about to apply this by amending the comment, but... it's not just the comment (hence it needs to be re-tested a bit): OPT_MAX should be 307 now, otherwise you don't actually use the extra byte. -- StefanoThe option 255 (end of options) do not need the length byte, this change remove that allowing to have one extra byte at other dynamic options. Signed-off-by: Enrique Llorente <ellorent(a)redhat.com>Thanks, change is good. However, could you also update the comment on OPT_MAX's definition that appears to have the same error in it.
On Wed, Feb 12, 2025 at 2:38 AM Stefano Brivio <sbrivio(a)redhat.com> wrote:On Wed, 12 Feb 2025 12:14:32 +1100 David Gibson <david(a)gibson.dropbear.id.au> wrote:Good catch, changing.On Tue, Feb 11, 2025 at 12:14:34PM +0100, Enrique Llorente wrote:I was about to apply this by amending the comment, but... it's not just the comment (hence it needs to be re-tested a bit): OPT_MAX should be 307 now, otherwise you don't actually use the extra byte.The option 255 (end of options) do not need the length byte, this change remove that allowing to have one extra byte at other dynamic options. Signed-off-by: Enrique Llorente <ellorent(a)redhat.com>Thanks, change is good. However, could you also update the comment on OPT_MAX's definition that appears to have the same error in it.-- Stefano-- Quique Llorente CNV networking Senior Software Engineer Red Hat EMEA ellorent(a)redhat.com @RedHat Red Hat Red Hat