From: Alok Tiwari Date: Mon, 15 Sep 2025 18:37:57 +0000 (-0700) Subject: scsi: libfc: Fix potential buffer overflow in fc_ct_ms_fill() X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=072fdd4b0be9b9051bdf75f36d0227aa705074ba;p=users%2Fhch%2Fmisc.git scsi: libfc: Fix potential buffer overflow in fc_ct_ms_fill() The fc_ct_ms_fill() helper currently formats the OS name and version into entry->value using "%s v%s". Since init_utsname()->sysname and ->release are unbounded strings, snprintf() may attempt to write more than FC_FDMI_HBA_ATTR_OSNAMEVERSION_LEN bytes, triggering a -Wformat-truncation warning with W=1. In file included from drivers/scsi/libfc/fc_elsct.c:18: drivers/scsi/libfc/fc_encode.h: In function ‘fc_ct_ms_fill.constprop’: drivers/scsi/libfc/fc_encode.h:359:30: error: ‘%s’ directive output may be truncated writing up to 64 bytes into a region of size between 62 and 126 [-Werror=format-truncation=] 359 | "%s v%s", | ^~ 360 | init_utsname()->sysname, 361 | init_utsname()->release); | ~~~~~~~~~~~~~~~~~~~~~~~ drivers/scsi/libfc/fc_encode.h:357:17: note: ‘snprintf’ output between 3 and 131 bytes into a destination of size 128 357 | snprintf((char *)&entry->value, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 358 | FC_FDMI_HBA_ATTR_OSNAMEVERSION_LEN, | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 359 | "%s v%s", | ~~~~~~~~~ 360 | init_utsname()->sysname, | ~~~~~~~~~~~~~~~~~~~~~~~~ 361 | init_utsname()->release); | ~~~~~~~~~~~~~~~~~~~~~~~~ Fix this by using "%.62s v%.62s", which ensures sysname and release are truncated to fit within the 128-byte field defined by FC_FDMI_HBA_ATTR_OSNAMEVERSION_LEN. [mkp: clarified commit description] Signed-off-by: Alok Tiwari Signed-off-by: Martin K. Petersen --- diff --git a/drivers/scsi/libfc/fc_encode.h b/drivers/scsi/libfc/fc_encode.h index 02e31db31d68..e046091a549a 100644 --- a/drivers/scsi/libfc/fc_encode.h +++ b/drivers/scsi/libfc/fc_encode.h @@ -356,7 +356,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport, put_unaligned_be16(len, &entry->len); snprintf((char *)&entry->value, FC_FDMI_HBA_ATTR_OSNAMEVERSION_LEN, - "%s v%s", + "%.62s v%.62s", init_utsname()->sysname, init_utsname()->release);