[commit] master: overflow-check ranges[] in imap_set_range()

[Oswald B. <os...@us...>]

commit 6b22c837f6aea82079db91c10220e4fae77a31e2
Author: Oswald Buddenhagen <os...@us...>
Date:   Wed Dec 29 21:55:53 2021 +0100

    overflow-check ranges[] in imap_set_range()
    
    amends 3d64f167.

 src/drv_imap.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/drv_imap.c b/src/drv_imap.c
index 1db59937..fb8d1650 100644
--- a/src/drv_imap.c
+++ b/src/drv_imap.c
@@ -2819,6 +2819,8 @@ typedef struct {
 	int flags;
 } imap_range_t;
 
+#define MAX_RANGES 4
+
 static void
 imap_set_range( imap_range_t *ranges, uint *nranges, int low_flags, int high_flags, uint maxlow )
 {
@@ -2830,6 +2832,8 @@ imap_set_range( imap_range_t *ranges, uint *nranges, int low_flags, int high_fla
 				continue; /* Range ends below split point; try next one. */
 			if (ranges[r].last != maxlow) {
 				/* Range does not end exactly at split point; need to split. */
+				if (*nranges == MAX_RANGES)
+					oob();
 				memmove( &ranges[r + 1], &ranges[r], ((*nranges)++ - r) * sizeof(*ranges) );
 				ranges[r].last = maxlow;
 				ranges[r + 1].first = maxlow + 1;
@@ -2883,7 +2887,7 @@ imap_load_box( store_t *gctx, uint minuid, uint maxuid, uint finduid, uint pairu
 		if (maxuid == UINT_MAX)
 			maxuid = ctx->uidnext - 1;
 		if (maxuid >= minuid) {
-			imap_range_t ranges[4];
+			imap_range_t ranges[MAX_RANGES];
 			ranges[0].first = minuid;
 			ranges[0].last = maxuid;
 			ranges[0].flags = 0;