From: Peter Maydell <peter.maydell@linaro.org> To: Alistair Francis <alistair23@gmail.com> Cc: "open list:RISC-V" <qemu-riscv@nongnu.org>, "Bin Meng" <bin.meng@windriver.com>, "Philippe Mathieu-Daudé" <f4bug@amsat.org>, "qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>, "Palmer Dabbelt" <palmer@dabbelt.com>, "Alistair Francis" <alistair.francis@wdc.com> Subject: Re: [PATCH] hw/riscv/virt.c: Assemble plic_hart_config string with g_strjoinv() Date: Fri, 13 Aug 2021 10:19:55 +0100 [thread overview] Message-ID: <CAFEAcA9kft4UNv0DFjRe_CLvsqNBzpqUePMYVTWiKzWmw=93nw@mail.gmail.com> (raw) In-Reply-To: <CAKmqyKNFpPJqQ5DTTvSQGBWfB9UW2xrhFf6DJQgB6Zt4ZGp+mw@mail.gmail.com> On Fri, 13 Aug 2021 at 01:57, Alistair Francis <alistair23@gmail.com> wrote: > > On Fri, Aug 13, 2021 at 2:17 AM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote: > > > > Hi Peter, > > > > On 8/12/21 4:46 PM, Peter Maydell wrote: > > > In the riscv virt machine init function, We assemble a string > > > plic_hart_config which is a comma-separated list of N copies of the > > > VIRT_PLIC_HART_CONFIG string. The code that does this has a > > > misunderstanding of the strncat() length argument. If the source > > > string is too large strncat() will write a maximum of length+1 bytes > > > (length bytes from the source string plus a trailing NUL), but the > > > code here assumes that it will write only length bytes at most. > > > > > > This isn't an actual bug because the code has correctly precalculated > > > the amount of memory it needs to allocate so that it will never be > > > too small (i.e. we could have used plain old strcat()), but it does > > > mean that the code looks like it has a guard against accidental > > > overrun when it doesn't. > > > > > > Rewrite the string handling here to use the glib g_strjoinv() > > > function, which means we don't need to do careful accountancy of > > > string lengths, and makes it clearer that what we're doing is > > > "create a comma-separated string". > > > > > > Fixes: Coverity 1460752 > > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > Thanks for fixing this Peter. Would you like this in for 6.1? No, this isn't 6.1 material -- as I note in the commit message, the current code isn't actually buggy, just a bit misleading. > If you want I can fix the other boards? That would be great, thanks! -- PMM
WARNING: multiple messages have this Message-ID (diff)
From: Peter Maydell <peter.maydell@linaro.org> To: Alistair Francis <alistair23@gmail.com> Cc: "Philippe Mathieu-Daudé" <f4bug@amsat.org>, "qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>, "Alistair Francis" <alistair.francis@wdc.com>, "Bin Meng" <bin.meng@windriver.com>, "Palmer Dabbelt" <palmer@dabbelt.com>, "open list:RISC-V" <qemu-riscv@nongnu.org> Subject: Re: [PATCH] hw/riscv/virt.c: Assemble plic_hart_config string with g_strjoinv() Date: Fri, 13 Aug 2021 10:19:55 +0100 [thread overview] Message-ID: <CAFEAcA9kft4UNv0DFjRe_CLvsqNBzpqUePMYVTWiKzWmw=93nw@mail.gmail.com> (raw) In-Reply-To: <CAKmqyKNFpPJqQ5DTTvSQGBWfB9UW2xrhFf6DJQgB6Zt4ZGp+mw@mail.gmail.com> On Fri, 13 Aug 2021 at 01:57, Alistair Francis <alistair23@gmail.com> wrote: > > On Fri, Aug 13, 2021 at 2:17 AM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote: > > > > Hi Peter, > > > > On 8/12/21 4:46 PM, Peter Maydell wrote: > > > In the riscv virt machine init function, We assemble a string > > > plic_hart_config which is a comma-separated list of N copies of the > > > VIRT_PLIC_HART_CONFIG string. The code that does this has a > > > misunderstanding of the strncat() length argument. If the source > > > string is too large strncat() will write a maximum of length+1 bytes > > > (length bytes from the source string plus a trailing NUL), but the > > > code here assumes that it will write only length bytes at most. > > > > > > This isn't an actual bug because the code has correctly precalculated > > > the amount of memory it needs to allocate so that it will never be > > > too small (i.e. we could have used plain old strcat()), but it does > > > mean that the code looks like it has a guard against accidental > > > overrun when it doesn't. > > > > > > Rewrite the string handling here to use the glib g_strjoinv() > > > function, which means we don't need to do careful accountancy of > > > string lengths, and makes it clearer that what we're doing is > > > "create a comma-separated string". > > > > > > Fixes: Coverity 1460752 > > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > Thanks for fixing this Peter. Would you like this in for 6.1? No, this isn't 6.1 material -- as I note in the commit message, the current code isn't actually buggy, just a bit misleading. > If you want I can fix the other boards? That would be great, thanks! -- PMM
next prev parent reply other threads:[~2021-08-13 9:21 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-12 14:46 [PATCH] hw/riscv/virt.c: Assemble plic_hart_config string with g_strjoinv() Peter Maydell 2021-08-12 14:46 ` Peter Maydell 2021-08-12 16:09 ` Philippe Mathieu-Daudé 2021-08-12 16:09 ` Philippe Mathieu-Daudé 2021-08-12 16:28 ` Peter Maydell 2021-08-12 16:28 ` Peter Maydell 2021-08-13 0:57 ` Alistair Francis 2021-08-13 0:57 ` Alistair Francis 2021-08-13 9:19 ` Peter Maydell [this message] 2021-08-13 9:19 ` Peter Maydell
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