[PATCH] hyperv: Avoid memleak in hypervDomainDefParsePhysicalDisk
From: Michal Privoznik <mprivozn@redhat.com> When parsing a physical disk, the @hostResouce is escaped once with the retval being stored into @hostEscaped. Then, it's escaped again, but the retval is stored into the very same variable, leading to a leak where intermediate value is lost. 256 bytes in 1 blocks are definitely lost in loss record 469 of 483 at 0x49543A0: realloc (vg_replace_malloc.c:1804) by 0x516C251: g_realloc (in /usr/lib64/libglib-2.0.so.0.8400.4) by 0x518BB7E: g_string_expand (in /usr/lib64/libglib-2.0.so.0.8400.4) by 0x518BFF9: g_string_insert_len (in /usr/lib64/libglib-2.0.so.0.8400.4) by 0x4A58B5F: g_string_append_len_inline (gstring.h:247) by 0x4A58B5F: virBufferAdd (virbuffer.c:164) by 0x4AFDA71: virStringReplace (virstring.c:708) by 0x4DA4381: hypervDomainDefParsePhysicalDisk (hyperv_driver.c:1375) by 0x4DA4A18: hypervDomainDefParseStorage (hyperv_driver.c:1487) by 0x4DA9E31: hypervDomainGetXMLDesc (hyperv_driver.c:2761) by 0x4DFB3E5: virDomainGetXMLDesc (libvirt-domain.c:2898) by 0x406D39B: cmdDumpXML (virsh-domain.c:10787) by 0x40B13B1: vshCommandRun (vsh.c:1383) Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/hyperv/hyperv_driver.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/src/hyperv/hyperv_driver.c b/src/hyperv/hyperv_driver.c index 8dd56f39dc..203bbeb8a5 100644 --- a/src/hyperv/hyperv_driver.c +++ b/src/hyperv/hyperv_driver.c @@ -1351,6 +1351,7 @@ hypervDomainDefParsePhysicalDisk(hypervPrivate *priv, virDomainDiskDef *disk = NULL; char **hostResource = entry->data->HostResource.data; g_autofree char *hostEscaped = NULL; + g_autofree char *hostEscapedTwice = NULL; g_autofree char *driveNumberStr = NULL; g_auto(virBuffer) query = VIR_BUFFER_INITIALIZER; int addr = -1, ctrlr_idx = -1; @@ -1373,12 +1374,12 @@ hypervDomainDefParsePhysicalDisk(hypervPrivate *priv, /* Query Msvm_DiskDrive for the DriveNumber */ hostEscaped = virStringReplace(*hostResource, "\\\"", "\""); - hostEscaped = virStringReplace(hostEscaped, "\\", "\\\\"); + hostEscapedTwice = virStringReplace(hostEscaped, "\\", "\\\\"); /* quotes must be preserved, so virBufferEscapeSQL can't be used */ virBufferAsprintf(&query, MSVM_DISKDRIVE_WQL_SELECT "WHERE __PATH='%s'", - hostEscaped); + hostEscapedTwice); if (hypervGetWmiClass(Msvm_DiskDrive, &diskdrive) < 0) goto cleanup; -- 2.52.0
On a Friday in 2026, Michal Privoznik via Devel wrote:
From: Michal Privoznik <mprivozn@redhat.com>
When parsing a physical disk, the @hostResouce is escaped once with the retval being stored into @hostEscaped. Then, it's escaped again, but the retval is stored into the very same variable, leading to a leak where intermediate value is lost.
256 bytes in 1 blocks are definitely lost in loss record 469 of 483 at 0x49543A0: realloc (vg_replace_malloc.c:1804) by 0x516C251: g_realloc (in /usr/lib64/libglib-2.0.so.0.8400.4) by 0x518BB7E: g_string_expand (in /usr/lib64/libglib-2.0.so.0.8400.4) by 0x518BFF9: g_string_insert_len (in /usr/lib64/libglib-2.0.so.0.8400.4) by 0x4A58B5F: g_string_append_len_inline (gstring.h:247) by 0x4A58B5F: virBufferAdd (virbuffer.c:164) by 0x4AFDA71: virStringReplace (virstring.c:708) by 0x4DA4381: hypervDomainDefParsePhysicalDisk (hyperv_driver.c:1375) by 0x4DA4A18: hypervDomainDefParseStorage (hyperv_driver.c:1487) by 0x4DA9E31: hypervDomainGetXMLDesc (hyperv_driver.c:2761) by 0x4DFB3E5: virDomainGetXMLDesc (libvirt-domain.c:2898) by 0x406D39B: cmdDumpXML (virsh-domain.c:10787) by 0x40B13B1: vshCommandRun (vsh.c:1383)
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/hyperv/hyperv_driver.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/src/hyperv/hyperv_driver.c b/src/hyperv/hyperv_driver.c index 8dd56f39dc..203bbeb8a5 100644 --- a/src/hyperv/hyperv_driver.c +++ b/src/hyperv/hyperv_driver.c @@ -1351,6 +1351,7 @@ hypervDomainDefParsePhysicalDisk(hypervPrivate *priv, virDomainDiskDef *disk = NULL; char **hostResource = entry->data->HostResource.data; g_autofree char *hostEscaped = NULL; + g_autofree char *hostEscapedTwice = NULL; g_autofree char *driveNumberStr = NULL; g_auto(virBuffer) query = VIR_BUFFER_INITIALIZER; int addr = -1, ctrlr_idx = -1; @@ -1373,12 +1374,12 @@ hypervDomainDefParsePhysicalDisk(hypervPrivate *priv,
/* Query Msvm_DiskDrive for the DriveNumber */ hostEscaped = virStringReplace(*hostResource, "\\\"", "\""); - hostEscaped = virStringReplace(hostEscaped, "\\", "\\\\"); + hostEscapedTwice = virStringReplace(hostEscaped, "\\", "\\\\");
Let's hope it does not escape for the third time.
/* quotes must be preserved, so virBufferEscapeSQL can't be used */ virBufferAsprintf(&query, MSVM_DISKDRIVE_WQL_SELECT "WHERE __PATH='%s'", - hostEscaped); + hostEscapedTwice);
Reviewed-by: Ján Tomko <jtomko@redhat.com> Jano
participants (2)
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Ján Tomko -
Michal Privoznik